TIP #491 implementation: Threading Support: phasing out non-threaded builds

34 files changed, 446 insertions, 696 deletions

diff --git a/generic/tcl.h b/generic/tcl.h
index a5f85df..ff82bd6 100644
--- a/generic/tcl.h
+++ b/generic/tcl.h
@@ -91,6 +91,10 @@ extern "C" {
 #endif
 #endif /* !TCL_NO_DEPRECATED */
 
+#ifndef TCL_THREADS
+#   define TCL_THREADS 1
+#endif
+
 /*
  * A special definition used to allow this header file to be included from
  * windows resource files so that they can obtain version information.
@@ -107,7 +111,7 @@ extern "C" {
  * using threads.
  */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 #define TCL_DECLARE_MUTEX(name) static Tcl_Mutex name;
 #else
 #define TCL_DECLARE_MUTEX(name)
@@ -2561,7 +2565,7 @@ EXTERN void		Tcl_GetMemoryInfo(Tcl_DString *dsPtr);
  * when compiling without thread support.
  */
 
-#ifndef TCL_THREADS
+#if defined(TCL_THREADS) && !TCL_THREADS
 #undef  Tcl_MutexLock
 #define Tcl_MutexLock(mutexPtr)
 #undef  Tcl_MutexUnlock
@@ -2574,7 +2578,7 @@ EXTERN void		Tcl_GetMemoryInfo(Tcl_DString *dsPtr);
 #define Tcl_ConditionWait(condPtr, mutexPtr, timePtr)
 #undef  Tcl_ConditionFinalize
 #define Tcl_ConditionFinalize(condPtr)
-#endif /* TCL_THREADS */
+#endif /* !TCL_THREADS */
 
 /*
  *----------------------------------------------------------------------------
diff --git a/generic/tclAlloc.c b/generic/tclAlloc.c
index 8a4b1c8..e04e9c6 100644
--- a/generic/tclAlloc.c
+++ b/generic/tclAlloc.c
@@ -22,7 +22,7 @@
  */
 
 #include "tclInt.h"
-#if !defined(TCL_THREADS) || !defined(USE_THREAD_ALLOC)
+#if (defined(TCL_THREADS) && !TCL_THREADS) || !defined(USE_THREAD_ALLOC)
 
 #if USE_TCLALLOC
 
@@ -121,7 +121,7 @@ static struct block bigBlocks={	/* Big blocks aren't suballocated. */
  * variable.
  */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 static Tcl_Mutex *allocMutexPtr;
 #endif
 static int allocInit = 0;
@@ -171,7 +171,7 @@ TclInitAlloc(void)
 {
     if (!allocInit) {
 	allocInit = 1;
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	allocMutexPtr = Tcl_GetAllocMutex();
 #endif
     }
diff --git a/generic/tclBasic.c b/generic/tclBasic.c
index 2ebed06..e20c1b3 100644
--- a/generic/tclBasic.c
+++ b/generic/tclBasic.c
@@ -749,7 +749,7 @@ Tcl_CreateInterp(void)
      * cache was already initialised by the call to alloc the interp struct.
      */
 
-#if defined(TCL_THREADS) && defined(USE_THREAD_ALLOC)
+#if (!defined(TCL_THREADS) || TCL_THREADS) && defined(USE_THREAD_ALLOC)
     iPtr->allocCache = TclpGetAllocCache();
 #else
     iPtr->allocCache = NULL;
@@ -964,7 +964,7 @@ Tcl_CreateInterp(void)
 #endif /* !TCL_NO_DEPRECATED */
     TclpSetVariables(interp);
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     /*
      * The existence of the "threaded" element of the tcl_platform array
      * indicates that this particular Tcl shell has been compiled with threads
diff --git a/generic/tclCkalloc.c b/generic/tclCkalloc.c
index de767f9..e00ac19 100644
--- a/generic/tclCkalloc.c
+++ b/generic/tclCkalloc.c
@@ -156,7 +156,7 @@ TclInitDbCkalloc(void)
     if (!ckallocInit) {
 	ckallocInit = 1;
 	ckallocMutexPtr = Tcl_GetAllocMutex();
-#ifndef TCL_THREADS
+#if defined(TCL_THREADS) && !TCL_THREADS
 	/* Silence compiler warning */
 	(void)ckallocMutexPtr;
 #endif
diff --git a/generic/tclEvent.c b/generic/tclEvent.c
index 93cf983..f8ad1ae 100644
--- a/generic/tclEvent.c
+++ b/generic/tclEvent.c
@@ -100,7 +100,7 @@ typedef struct ThreadSpecificData {
 } ThreadSpecificData;
 static Tcl_ThreadDataKey dataKey;
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 typedef struct {
     Tcl_ThreadCreateProc *proc;	/* Main() function of the thread */
     ClientData clientData;	/* The one argument to Main() */
@@ -1043,7 +1043,7 @@ TclInitSubsystems(void)
 #if USE_TCLALLOC
 	    TclInitAlloc();		/* Process wide mutex init */
 #endif
-#if defined(TCL_THREADS) && defined(USE_THREAD_ALLOC)
+#if (!defined(TCL_THREADS) || TCL_THREADS) && defined(USE_THREAD_ALLOC)
 	    TclInitThreadAlloc();	/* Setup thread allocator caches */
 #endif
 #ifdef TCL_MEM_DEBUG
@@ -1220,7 +1220,7 @@ Tcl_Finalize(void)
      * Close down the thread-specific object allocator.
      */
 
-#if defined(TCL_THREADS) && defined(USE_THREAD_ALLOC)
+#if (!defined(TCL_THREADS) || TCL_THREADS) && defined(USE_THREAD_ALLOC)
     TclFinalizeThreadAlloc();
 #endif
 
@@ -1538,7 +1538,7 @@ Tcl_UpdateObjCmd(
     return TCL_OK;
 }
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /*
  *----------------------------------------------------------------------
  *
@@ -1601,7 +1601,7 @@ Tcl_CreateThread(
     int flags)			/* Flags controlling behaviour of the new
 				 * thread. */
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     ThreadClientData *cdPtr = ckalloc(sizeof(ThreadClientData));
     int result;
 
diff --git a/generic/tclIORChan.c b/generic/tclIORChan.c
index 8e1496d..1553cd0 100644
--- a/generic/tclIORChan.c
+++ b/generic/tclIORChan.c
@@ -39,7 +39,7 @@ static int		ReflectOutput(ClientData clientData, const char *buf,
 			    int toWrite, int *errorCodePtr);
 static void		ReflectWatch(ClientData clientData, int mask);
 static int		ReflectBlock(ClientData clientData, int mode);
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 static void		ReflectThread(ClientData clientData, int action);
 static int		ReflectEventRun(Tcl_Event *ev, int flags);
 static int		ReflectEventDelete(Tcl_Event *ev, ClientData cd);
@@ -76,7 +76,7 @@ static const Tcl_ChannelType tclRChannelType = {
     NULL,		   /* Flush channel. Not used by core.	NULL'able */
     NULL,		   /* Handle events.			NULL'able */
     ReflectSeekWide,	   /* Move access point (64 bit).	NULL'able */
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     ReflectThread,         /* thread action, tracking owner */
 #else
     NULL,		   /* thread action */
@@ -97,7 +97,7 @@ typedef struct {
 				 * interpreter/thread containing its Tcl
 				 * command is gone.
 				 */
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     Tcl_ThreadId thread;	/* Thread the 'interp' belongs to. == Handler thread */
     Tcl_ThreadId owner;         /* Thread owning the structure.    == Channel thread */
 #endif
@@ -201,7 +201,7 @@ typedef enum {
 #define NEGIMPL(a,b)
 #define HAS(x,f)	(x & FLAG(f))
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /*
  * Thread specific types and structures.
  *
@@ -451,7 +451,7 @@ static const char *msg_read_toomuch = "{read delivered more than requested}";
 static const char *msg_write_toomuch = "{write wrote more than requested}";
 static const char *msg_write_nothing = "{write wrote nothing}";
 static const char *msg_seek_beforestart = "{Tried to seek before origin}";
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 static const char *msg_send_originlost = "{Channel thread lost}";
 #endif /* TCL_THREADS */
 static const char *msg_send_dstlost    = "{Owner lost}";
@@ -706,7 +706,7 @@ TclChanCreateObjCmd(
 	Tcl_Panic("TclChanCreateObjCmd: duplicate channel names");
     }
     Tcl_SetHashValue(hPtr, chan);
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     rcmPtr = GetThreadReflectedChannelMap();
     hPtr = Tcl_CreateHashEntry(&rcmPtr->map, chanPtr->state->channelName,
 	    &isNew);
@@ -750,7 +750,7 @@ TclChanCreateObjCmd(
  *----------------------------------------------------------------------
  */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 typedef struct {
     Tcl_Event header;
     ReflectedChannel *rcPtr;
@@ -917,11 +917,11 @@ TclChanPostEventObjCmd(
      * We have the channel and the events to post.
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rcPtr->owner == rcPtr->thread) {
 #endif
         Tcl_NotifyChannel(chan, events);
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     } else {
         ReflectEvent *ev = ckalloc(sizeof(ReflectEvent));
 
@@ -1137,7 +1137,7 @@ ReflectClose(
 	 * if lost?
 	 */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	if (rcPtr->thread != Tcl_GetCurrentThread()) {
 	    ForwardParam p;
 
@@ -1169,7 +1169,7 @@ ReflectClose(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rcPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -1216,7 +1216,7 @@ ReflectClose(
 		Tcl_DeleteHashEntry(hPtr);
 	    }
 	}
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	rcmPtr = GetThreadReflectedChannelMap();
 	hPtr = Tcl_FindHashEntry(&rcmPtr->map,
 		Tcl_GetChannelName(rcPtr->chan));
@@ -1267,7 +1267,7 @@ ReflectInput(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rcPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -1373,7 +1373,7 @@ ReflectOutput(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rcPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -1502,7 +1502,7 @@ ReflectSeekWide(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rcPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -1625,7 +1625,7 @@ ReflectWatch(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rcPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -1683,7 +1683,7 @@ ReflectBlock(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rcPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -1719,7 +1719,7 @@ ReflectBlock(
     return errorNum;
 }
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /*
  *----------------------------------------------------------------------
  *
@@ -1789,7 +1789,7 @@ ReflectSetOption(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rcPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -1868,7 +1868,7 @@ ReflectGetOption(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rcPtr->thread != Tcl_GetCurrentThread()) {
 	int opcode;
 	ForwardParam p;
@@ -2131,7 +2131,7 @@ NewReflectedChannel(
     rcPtr->chan = NULL;
     rcPtr->interp = interp;
     rcPtr->dead = 0;
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     rcPtr->thread = Tcl_GetCurrentThread();
 #endif
     rcPtr->mode = mode;
@@ -2506,7 +2506,7 @@ DeleteReflectedChannelMap(
     Tcl_HashEntry *hPtr;	 /* Search variable. */
     ReflectedChannel *rcPtr;
     Tcl_Channel chan;
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     ForwardingResult *resultPtr;
     ForwardingEvent *evPtr;
     ForwardParam *paramPtr;
@@ -2536,7 +2536,7 @@ DeleteReflectedChannelMap(
     Tcl_DeleteHashTable(&rcmPtr->map);
     ckfree(&rcmPtr->map);
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     /*
      * The origin interpreter for one or more reflected channels is gone.
      */
@@ -2622,7 +2622,7 @@ DeleteReflectedChannelMap(
 #endif
 }
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /*
  *----------------------------------------------------------------------
  *
diff --git a/generic/tclIORTrans.c b/generic/tclIORTrans.c
index fe2e458..03fadd1 100644
--- a/generic/tclIORTrans.c
+++ b/generic/tclIORTrans.c
@@ -127,7 +127,7 @@ typedef struct {
 				 * in the argv, see below. The separate field
 				 * gives us direct access, needed when working
 				 * with the reflection maps. */
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     Tcl_ThreadId thread;	/* Thread the 'interp' belongs to. */
 #endif
 
@@ -220,7 +220,7 @@ typedef enum {
 #define NEGIMPL(a,b)
 #define HAS(x,f)	(x & FLAG(f))
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /*
  * Thread specific types and structures.
  *
@@ -438,7 +438,7 @@ static void		DeleteReflectedTransformMap(ClientData clientData,
 
 static const char *msg_read_unsup = "{read not supported by Tcl driver}";
 static const char *msg_write_unsup = "{write not supported by Tcl driver}";
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 static const char *msg_send_originlost = "{Channel thread lost}";
 static const char *msg_send_dstlost = "{Owner lost}";
 #endif /* TCL_THREADS */
@@ -699,7 +699,7 @@ TclChanPushObjCmd(
 	Tcl_Panic("TclChanPushObjCmd: duplicate transformation handle");
     }
     Tcl_SetHashValue(hPtr, rtPtr);
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     rtmPtr = GetThreadReflectedTransformMap();
     hPtr = Tcl_CreateHashEntry(&rtmPtr->map, TclGetString(rtId), &isNew);
     Tcl_SetHashValue(hPtr, rtPtr);
@@ -911,7 +911,7 @@ ReflectClose(
 	 * if lost?
 	 */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	if (rtPtr->thread != Tcl_GetCurrentThread()) {
 	    ForwardParam p;
 
@@ -938,7 +938,7 @@ ReflectClose(
 
     if (HAS(rtPtr->methods, METH_DRAIN) && !rtPtr->readIsDrained) {
 	if (!TransformDrain(rtPtr, &errorCode)) {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	    if (rtPtr->thread != Tcl_GetCurrentThread()) {
 		Tcl_EventuallyFree(rtPtr,
 			(Tcl_FreeProc *) FreeReflectedTransform);
@@ -952,7 +952,7 @@ ReflectClose(
 
     if (HAS(rtPtr->methods, METH_FLUSH)) {
 	if (!TransformFlush(rtPtr, &errorCode, FLUSH_WRITE)) {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	    if (rtPtr->thread != Tcl_GetCurrentThread()) {
 		Tcl_EventuallyFree(rtPtr,
 			(Tcl_FreeProc *) FreeReflectedTransform);
@@ -968,7 +968,7 @@ ReflectClose(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rtPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -1025,7 +1025,7 @@ ReflectClose(
 	 * under a channel by deleting the owning thread.
 	 */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	rtmPtr = GetThreadReflectedTransformMap();
 	hPtr = Tcl_FindHashEntry(&rtmPtr->map, TclGetString(rtPtr->handle));
 	if (hPtr) {
@@ -1767,7 +1767,7 @@ NewReflectedTransform(
 
     rtPtr->chan = NULL;
     rtPtr->methods = 0;
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     rtPtr->thread = Tcl_GetCurrentThread();
 #endif
     rtPtr->parent = parentChan;
@@ -2152,7 +2152,7 @@ DeleteReflectedTransformMap(
     Tcl_HashSearch hSearch;	 /* Search variable. */
     Tcl_HashEntry *hPtr;	 /* Search variable. */
     ReflectedTransform *rtPtr;
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     ForwardingResult *resultPtr;
     ForwardingEvent *evPtr;
     ForwardParam *paramPtr;
@@ -2182,7 +2182,7 @@ DeleteReflectedTransformMap(
     Tcl_DeleteHashTable(&rtmPtr->map);
     ckfree(&rtmPtr->map);
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     /*
      * The origin interpreter for one or more reflected channels is gone.
      */
@@ -2254,7 +2254,7 @@ DeleteReflectedTransformMap(
 #endif /* TCL_THREADS */
 }
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /*
  *----------------------------------------------------------------------
  *
@@ -3088,7 +3088,7 @@ TransformRead(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rtPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -3144,7 +3144,7 @@ TransformWrite(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rtPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -3210,7 +3210,7 @@ TransformDrain(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rtPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -3260,7 +3260,7 @@ TransformFlush(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rtPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -3315,7 +3315,7 @@ TransformClear(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rtPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
@@ -3347,7 +3347,7 @@ TransformLimit(
      * Are we in the correct thread?
      */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (rtPtr->thread != Tcl_GetCurrentThread()) {
 	ForwardParam p;
 
diff --git a/generic/tclInt.h b/generic/tclInt.h
index 8f5d8ba..eb1ae68 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -4200,6 +4200,10 @@ typedef const char *TclDTraceStr;
 	} \
     }
 
+#if (!defined(TCL_THREADS) || TCL_THREADS) && !defined(USE_THREAD_ALLOC)
+#   define USE_THREAD_ALLOC 1
+#endif
+
 #if defined(PURIFY)
 
 /*
@@ -4217,7 +4221,7 @@ typedef const char *TclDTraceStr;
 
 #undef USE_THREAD_ALLOC
 #undef USE_TCLALLOC
-#elif defined(TCL_THREADS) && defined(USE_THREAD_ALLOC)
+#elif (!defined(TCL_THREADS) || TCL_THREADS) && defined(USE_THREAD_ALLOC)
 
 /*
  * The TCL_THREADS mode is like the regular mode but allocates Tcl_Obj's from
@@ -4282,7 +4286,7 @@ MODULE_SCOPE void	TclpFreeAllocCache(void *);
 #   define USE_TCLALLOC 0
 #endif
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /* declared in tclObj.c */
 MODULE_SCOPE Tcl_Mutex	tclObjMutex;
 #endif
diff --git a/generic/tclObj.c b/generic/tclObj.c
index 7b9488e..0cd04ef 100644
--- a/generic/tclObj.c
+++ b/generic/tclObj.c
@@ -37,7 +37,7 @@ Tcl_Obj *tclFreeObjList = NULL;
  * TclNewObj macro, however, so must be visible.
  */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 MODULE_SCOPE Tcl_Mutex tclObjMutex;
 Tcl_Mutex tclObjMutex;
 #endif
@@ -50,7 +50,7 @@ Tcl_Mutex tclObjMutex;
 
 char tclEmptyString = '\0';
 
-#if defined(TCL_MEM_DEBUG) && defined(TCL_THREADS)
+#if (!defined(TCL_THREADS) || TCL_THREADS) && defined(TCL_MEM_DEBUG)
 /*
  * Structure for tracking the source file and line number where a given
  * Tcl_Obj was allocated.  We also track the pointer to the Tcl_Obj itself,
@@ -87,7 +87,7 @@ typedef struct {
                                  * tclCompile.h for the definition of this
                                  * structure, and for references to all
                                  * related places in the core. */
-#if defined(TCL_MEM_DEBUG) && defined(TCL_THREADS)
+#if (!defined(TCL_THREADS) || TCL_THREADS) && defined(TCL_MEM_DEBUG)
     Tcl_HashTable *objThreadMap;/* Thread local table that is used to check
                                  * that a Tcl_Obj was not allocated by some
                                  * other thread. */
@@ -156,7 +156,7 @@ typedef struct PendingObjData {
 /*
  * Macro to set up the local reference to the deletion context.
  */
-#ifndef TCL_THREADS
+#if defined(TCL_THREADS) && !TCL_THREADS
 static PendingObjData pendingObjData;
 #define ObjInitDeletionContext(contextPtr) \
     PendingObjData *const contextPtr = &pendingObjData
@@ -452,7 +452,7 @@ TclInitObjSubsystem(void)
 void
 TclFinalizeThreadObjects(void)
 {
-#if defined(TCL_MEM_DEBUG) && defined(TCL_THREADS)
+#if (!defined(TCL_THREADS) || TCL_THREADS) && defined(TCL_MEM_DEBUG)
     Tcl_HashEntry *hPtr;
     Tcl_HashSearch hSearch;
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
@@ -1009,7 +1009,7 @@ void
 TclDbDumpActiveObjects(
     FILE *outFile)
 {
-#if defined(TCL_MEM_DEBUG) && defined(TCL_THREADS)
+#if (!defined(TCL_THREADS) || TCL_THREADS) && defined(TCL_MEM_DEBUG)
     Tcl_HashSearch hSearch;
     Tcl_HashEntry *hPtr;
     Tcl_HashTable *tablePtr;
@@ -1069,7 +1069,7 @@ TclDbInitNewObj(
     objPtr->length = 0;
     objPtr->typePtr = NULL;
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     /*
      * Add entry to a thread local map used to check if a Tcl_Obj was
      * allocated by the currently executing thread.
@@ -1305,7 +1305,7 @@ TclFreeObj(
 
     ObjInitDeletionContext(context);
 
-# ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     /*
      * Check to make sure that the Tcl_Obj was allocated by the current
      * thread. Don't do this check when shutting down since thread local
@@ -3598,7 +3598,7 @@ Tcl_DbIncrRefCount(
 	Tcl_Panic("incrementing refCount of previously disposed object");
     }
 
-# ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     /*
      * Check to make sure that the Tcl_Obj was allocated by the current
      * thread. Don't do this check when shutting down since thread local
@@ -3661,7 +3661,7 @@ Tcl_DbDecrRefCount(
 	Tcl_Panic("decrementing refCount of previously disposed object");
     }
 
-# ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     /*
      * Check to make sure that the Tcl_Obj was allocated by the current
      * thread. Don't do this check when shutting down since thread local
@@ -3726,7 +3726,7 @@ Tcl_DbIsShared(
 	Tcl_Panic("checking whether previously disposed object is shared");
     }
 
-# ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     /*
      * Check to make sure that the Tcl_Obj was allocated by the current
      * thread. Don't do this check when shutting down since thread local
diff --git a/generic/tclPkgConfig.c b/generic/tclPkgConfig.c
index 466d535..a456a14 100644
--- a/generic/tclPkgConfig.c
+++ b/generic/tclPkgConfig.c
@@ -40,7 +40,7 @@
  * configuration information.
  */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 #  define  CFG_THREADED		"1"
 #else
 #  define  CFG_THREADED		"0"
diff --git a/generic/tclTest.c b/generic/tclTest.c
index 2ddb595..b4d249f 100644
--- a/generic/tclTest.c
+++ b/generic/tclTest.c
@@ -161,7 +161,7 @@ static TestChannel *firstDetached;
 
 static int		AsyncHandlerProc(ClientData clientData,
 			    Tcl_Interp *interp, int code);
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 static Tcl_ThreadCreateType AsyncThreadProc(ClientData);
 #endif
 static void		CleanupTestSetassocdataTests(
@@ -722,7 +722,7 @@ Tcltest_Init(
     if (Procbodytest_Init(interp) != TCL_OK) {
 	return TCL_ERROR;
     }
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (TclThread_Init(interp) != TCL_OK) {
 	return TCL_ERROR;
     }
@@ -902,7 +902,7 @@ TestasyncCmd(
 	Tcl_SetObjResult(interp, Tcl_NewStringObj(argv[3], -1));
 	Tcl_MutexUnlock(&asyncTestMutex);
 	return code;
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     } else if (strcmp(argv[1], "marklater") == 0) {
 	if (argc != 3) {
 	    goto wrongNumArgs;
@@ -999,7 +999,7 @@ AsyncHandlerProc(
  *----------------------------------------------------------------------
  */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 static Tcl_ThreadCreateType
 AsyncThreadProc(
     ClientData clientData)	/* Parameter is the id of a
diff --git a/generic/tclThread.c b/generic/tclThread.c
index 198fa6a..a70f1aa 100644
--- a/generic/tclThread.c
+++ b/generic/tclThread.c
@@ -46,7 +46,7 @@ static void		RememberSyncObject(void *objPtr,
  * table.
  */
 
-#ifndef TCL_THREADS
+#if defined(TCL_THREADS) && !TCL_THREADS
 #undef Tcl_MutexLock
 #undef Tcl_MutexUnlock
 #undef Tcl_MutexFinalize
@@ -79,7 +79,7 @@ Tcl_GetThreadData(
     int size)			/* Size of storage block */
 {
     void *result;
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     /*
      * Initialize the key for this thread.
      */
@@ -126,7 +126,7 @@ TclThreadDataKeyGet(
     Tcl_ThreadDataKey *keyPtr)	/* Identifier for the data chunk. */
 
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     return TclThreadStorageKeyGet(keyPtr);
 #else /* TCL_THREADS */
     return *keyPtr;
@@ -273,7 +273,7 @@ void
 Tcl_MutexFinalize(
     Tcl_Mutex *mutexPtr)
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     TclpFinalizeMutex(mutexPtr);
 #endif
     TclpMasterLock();
@@ -326,7 +326,7 @@ void
 Tcl_ConditionFinalize(
     Tcl_Condition *condPtr)
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     TclpFinalizeCondition(condPtr);
 #endif
     TclpMasterLock();
@@ -356,7 +356,7 @@ void
 TclFinalizeThreadData(int quick)
 {
     TclFinalizeThreadDataThread();
-#if defined(TCL_THREADS) && defined(USE_THREAD_ALLOC)
+#if (!defined(TCL_THREADS) || TCL_THREADS) && defined(USE_THREAD_ALLOC)
     if (!quick) {
 	/*
 	 * Quick exit principle makes it useless to terminate allocators
@@ -389,7 +389,7 @@ TclFinalizeSynchronization(void)
     int i;
     void *blockPtr;
     Tcl_ThreadDataKey *keyPtr;
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     Tcl_Mutex *mutexPtr;
     Tcl_Condition *condPtr;
 
@@ -413,7 +413,7 @@ TclFinalizeSynchronization(void)
     keyRecord.max = 0;
     keyRecord.num = 0;
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     /*
      * Call thread storage master cleanup.
      */
@@ -473,12 +473,12 @@ Tcl_ExitThread(
     int status)
 {
     Tcl_FinalizeThread();
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     TclpThreadExit(status);
 #endif
 }
 
-#ifndef TCL_THREADS
+#if defined(TCL_THREADS) && !TCL_THREADS
 
 /*
  *----------------------------------------------------------------------
diff --git a/generic/tclThreadAlloc.c b/generic/tclThreadAlloc.c
index 8077de4..c8132a5 100644
--- a/generic/tclThreadAlloc.c
+++ b/generic/tclThreadAlloc.c
@@ -13,7 +13,7 @@
  */
 
 #include "tclInt.h"
-#if defined(TCL_THREADS) && defined(USE_THREAD_ALLOC)
+#if (!defined(TCL_THREADS) || TCL_THREADS) && defined(USE_THREAD_ALLOC)
 
 /*
  * If range checking is enabled, an additional byte will be allocated to store
diff --git a/generic/tclThreadStorage.c b/generic/tclThreadStorage.c
index 755a461..d925b04 100644
--- a/generic/tclThreadStorage.c
+++ b/generic/tclThreadStorage.c
@@ -13,7 +13,7 @@
 
 #include "tclInt.h"
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 #include <signal.h>
 
 /*
diff --git a/generic/tclThreadTest.c b/generic/tclThreadTest.c
index a008799..dce15eb 100644
--- a/generic/tclThreadTest.c
+++ b/generic/tclThreadTest.c
@@ -18,7 +18,7 @@
 #endif
 #include "tclInt.h"
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /*
  * Each thread has an single instance of the following structure. There is one
  * instance of this structure per thread even if that thread contains multiple
diff --git a/unix/configure b/unix/configure
index 36bc4b9..4e3e06f 100755
--- a/unix/configure
+++ b/unix/configure
@@ -699,7 +699,6 @@ ZLIB_INCLUDE
 ZLIB_SRCS
 ZLIB_OBJS
 TCLSH_PROG
-TCL_THREADS
 EGREP
 GREP
 CPP
@@ -755,7 +754,6 @@ enable_option_checking
 enable_man_symlinks
 enable_man_compression
 enable_man_suffix
-enable_threads
 with_encoding
 enable_shared
 enable_64bit
@@ -1395,7 +1393,6 @@ Optional Features:
                           use STRING as a suffix to manpage file names
                           (default: no, tcl if enabled without
                           specifying STRING)
-  --enable-threads        build with threads (default: on)
   --enable-shared         build and link with shared libraries (default: on)
   --enable-64bit          enable 64bit support (default: off)
   --enable-64bit-vis      enable 64bit Sparc VIS support (default: off)
@@ -3911,95 +3908,135 @@ $as_echo "$tcl_cv_cc_pipe" >&6; }
 fi
 
 #------------------------------------------------------------------------
-# Threads support
+# Embedded configuration information, encoding to use for the values, TIP #59
 #------------------------------------------------------------------------
 
 
-    # Check whether --enable-threads was given.
-if test "${enable_threads+set}" = set; then :
-  enableval=$enable_threads; tcl_ok=$enableval
-else
-  tcl_ok=yes
+
+# Check whether --with-encoding was given.
+if test "${with_encoding+set}" = set; then :
+  withval=$with_encoding; with_tcencoding=${withval}
 fi
 
 
-    if test "${TCL_THREADS}" = 1; then
-	tcl_threaded_core=1;
-    fi
+    if test x"${with_tcencoding}" != x ; then
 
-    if test "$tcl_ok" = "yes" -o "${TCL_THREADS}" = 1; then
-	TCL_THREADS=1
-	# USE_THREAD_ALLOC tells us to try the special thread-based
-	# allocator that significantly reduces lock contention
+cat >>confdefs.h <<_ACEOF
+#define TCL_CFGVAL_ENCODING "${with_tcencoding}"
+_ACEOF
 
-$as_echo "#define USE_THREAD_ALLOC 1" >>confdefs.h
+    else
 
+$as_echo "#define TCL_CFGVAL_ENCODING \"iso8859-1\"" >>confdefs.h
 
-$as_echo "#define _REENTRANT 1" >>confdefs.h
+    fi
 
-	if test "`uname -s`" = "SunOS" ; then
 
-$as_echo "#define _POSIX_PTHREAD_SEMANTICS 1" >>confdefs.h
+#--------------------------------------------------------------------
+# Look for libraries that we will need when compiling the Tcl shell
+#--------------------------------------------------------------------
 
-	fi
 
-$as_echo "#define _THREAD_SAFE 1" >>confdefs.h
+    #--------------------------------------------------------------------
+    # On a few very rare systems, all of the libm.a stuff is
+    # already in libc.a.  Set compiler flags accordingly.
+    #--------------------------------------------------------------------
 
-	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for pthread_mutex_init in -lpthread" >&5
-$as_echo_n "checking for pthread_mutex_init in -lpthread... " >&6; }
-if ${ac_cv_lib_pthread_pthread_mutex_init+:} false; then :
+    ac_fn_c_check_func "$LINENO" "sin" "ac_cv_func_sin"
+if test "x$ac_cv_func_sin" = xyes; then :
+  MATH_LIBS=""
+else
+  MATH_LIBS="-lm"
+fi
+
+
+    #--------------------------------------------------------------------
+    # Interactive UNIX requires -linet instead of -lsocket, plus it
+    # needs net/errno.h to define the socket-related error codes.
+    #--------------------------------------------------------------------
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for main in -linet" >&5
+$as_echo_n "checking for main in -linet... " >&6; }
+if ${ac_cv_lib_inet_main+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lpthread  $LIBS"
+LIBS="-linet  $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
-/* Override any GCC internal prototype to avoid an error.
-   Use char because int might match the return type of a GCC
-   builtin and then its argument prototype would still apply.  */
-#ifdef __cplusplus
-extern "C"
-#endif
-char pthread_mutex_init ();
+
 int
 main ()
 {
-return pthread_mutex_init ();
+return main ();
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_pthread_pthread_mutex_init=yes
+  ac_cv_lib_inet_main=yes
 else
-  ac_cv_lib_pthread_pthread_mutex_init=no
+  ac_cv_lib_inet_main=no
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_pthread_pthread_mutex_init" >&5
-$as_echo "$ac_cv_lib_pthread_pthread_mutex_init" >&6; }
-if test "x$ac_cv_lib_pthread_pthread_mutex_init" = xyes; then :
-  tcl_ok=yes
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_inet_main" >&5
+$as_echo "$ac_cv_lib_inet_main" >&6; }
+if test "x$ac_cv_lib_inet_main" = xyes; then :
+  LIBS="$LIBS -linet"
+fi
+
+    ac_fn_c_check_header_mongrel "$LINENO" "net/errno.h" "ac_cv_header_net_errno_h" "$ac_includes_default"
+if test "x$ac_cv_header_net_errno_h" = xyes; then :
+
+
+$as_echo "#define HAVE_NET_ERRNO_H 1" >>confdefs.h
+
+fi
+
+
+
+    #--------------------------------------------------------------------
+    #	Check for the existence of the -lsocket and -lnsl libraries.
+    #	The order here is important, so that they end up in the right
+    #	order in the command line generated by make.  Here are some
+    #	special considerations:
+    #	1. Use "connect" and "accept" to check for -lsocket, and
+    #	   "gethostbyname" to check for -lnsl.
+    #	2. Use each function name only once:  can't redo a check because
+    #	   autoconf caches the results of the last check and won't redo it.
+    #	3. Use -lnsl and -lsocket only if they supply procedures that
+    #	   aren't already present in the normal libraries.  This is because
+    #	   IRIX 5.2 has libraries, but they aren't needed and they're
+    #	   bogus:  they goof up name resolution if used.
+    #	4. On some SVR4 systems, can't use -lsocket without -lnsl too.
+    #	   To get around this problem, check for both libraries together
+    #	   if -lsocket doesn't work by itself.
+    #--------------------------------------------------------------------
+
+    tcl_checkBoth=0
+    ac_fn_c_check_func "$LINENO" "connect" "ac_cv_func_connect"
+if test "x$ac_cv_func_connect" = xyes; then :
+  tcl_checkSocket=0
 else
-  tcl_ok=no
+  tcl_checkSocket=1
 fi
 
-	if test "$tcl_ok" = "no"; then
-	    # Check a little harder for __pthread_mutex_init in the same
-	    # library, as some systems hide it there until pthread.h is
-	    # defined.  We could alternatively do an AC_TRY_COMPILE with
-	    # pthread.h, but that will work with libpthread really doesn't
-	    # exist, like AIX 4.2.  [Bug: 4359]
-	    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for __pthread_mutex_init in -lpthread" >&5
-$as_echo_n "checking for __pthread_mutex_init in -lpthread... " >&6; }
-if ${ac_cv_lib_pthread___pthread_mutex_init+:} false; then :
+    if test "$tcl_checkSocket" = 1; then
+	ac_fn_c_check_func "$LINENO" "setsockopt" "ac_cv_func_setsockopt"
+if test "x$ac_cv_func_setsockopt" = xyes; then :
+
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for setsockopt in -lsocket" >&5
+$as_echo_n "checking for setsockopt in -lsocket... " >&6; }
+if ${ac_cv_lib_socket_setsockopt+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lpthread  $LIBS"
+LIBS="-lsocket  $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -4009,45 +4046,57 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 #ifdef __cplusplus
 extern "C"
 #endif
-char __pthread_mutex_init ();
+char setsockopt ();
 int
 main ()
 {
-return __pthread_mutex_init ();
+return setsockopt ();
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_pthread___pthread_mutex_init=yes
+  ac_cv_lib_socket_setsockopt=yes
 else
-  ac_cv_lib_pthread___pthread_mutex_init=no
+  ac_cv_lib_socket_setsockopt=no
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_pthread___pthread_mutex_init" >&5
-$as_echo "$ac_cv_lib_pthread___pthread_mutex_init" >&6; }
-if test "x$ac_cv_lib_pthread___pthread_mutex_init" = xyes; then :
-  tcl_ok=yes
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_socket_setsockopt" >&5
+$as_echo "$ac_cv_lib_socket_setsockopt" >&6; }
+if test "x$ac_cv_lib_socket_setsockopt" = xyes; then :
+  LIBS="$LIBS -lsocket"
 else
-  tcl_ok=no
+  tcl_checkBoth=1
 fi
 
-	fi
+fi
 
-	if test "$tcl_ok" = "yes"; then
-	    # The space is needed
-	    THREADS_LIBS=" -lpthread"
-	else
-	    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for pthread_mutex_init in -lpthreads" >&5
-$as_echo_n "checking for pthread_mutex_init in -lpthreads... " >&6; }
-if ${ac_cv_lib_pthreads_pthread_mutex_init+:} false; then :
+    fi
+    if test "$tcl_checkBoth" = 1; then
+	tk_oldLibs=$LIBS
+	LIBS="$LIBS -lsocket -lnsl"
+	ac_fn_c_check_func "$LINENO" "accept" "ac_cv_func_accept"
+if test "x$ac_cv_func_accept" = xyes; then :
+  tcl_checkNsl=0
+else
+  LIBS=$tk_oldLibs
+fi
+
+    fi
+    ac_fn_c_check_func "$LINENO" "gethostbyname" "ac_cv_func_gethostbyname"
+if test "x$ac_cv_func_gethostbyname" = xyes; then :
+
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for gethostbyname in -lnsl" >&5
+$as_echo_n "checking for gethostbyname in -lnsl... " >&6; }
+if ${ac_cv_lib_nsl_gethostbyname+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lpthreads  $LIBS"
+LIBS="-lnsl  $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -4057,43 +4106,46 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 #ifdef __cplusplus
 extern "C"
 #endif
-char pthread_mutex_init ();
+char gethostbyname ();
 int
 main ()
 {
-return pthread_mutex_init ();
+return gethostbyname ();
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_pthreads_pthread_mutex_init=yes
+  ac_cv_lib_nsl_gethostbyname=yes
 else
-  ac_cv_lib_pthreads_pthread_mutex_init=no
+  ac_cv_lib_nsl_gethostbyname=no
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_pthreads_pthread_mutex_init" >&5
-$as_echo "$ac_cv_lib_pthreads_pthread_mutex_init" >&6; }
-if test "x$ac_cv_lib_pthreads_pthread_mutex_init" = xyes; then :
-  tcl_ok=yes
-else
-  tcl_ok=no
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_nsl_gethostbyname" >&5
+$as_echo "$ac_cv_lib_nsl_gethostbyname" >&6; }
+if test "x$ac_cv_lib_nsl_gethostbyname" = xyes; then :
+  LIBS="$LIBS -lnsl"
 fi
 
-	    if test "$tcl_ok" = "yes"; then
-		# The space is needed
-		THREADS_LIBS=" -lpthreads"
-	    else
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for pthread_mutex_init in -lc" >&5
-$as_echo_n "checking for pthread_mutex_init in -lc... " >&6; }
-if ${ac_cv_lib_c_pthread_mutex_init+:} false; then :
+fi
+
+
+
+$as_echo "#define _REENTRANT 1" >>confdefs.h
+
+
+$as_echo "#define _THREAD_SAFE 1" >>confdefs.h
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for pthread_mutex_init in -lpthread" >&5
+$as_echo_n "checking for pthread_mutex_init in -lpthread... " >&6; }
+if ${ac_cv_lib_pthread_pthread_mutex_init+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lc  $LIBS"
+LIBS="-lpthread  $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -4113,30 +4165,35 @@ return pthread_mutex_init ();
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_c_pthread_mutex_init=yes
+  ac_cv_lib_pthread_pthread_mutex_init=yes
 else
-  ac_cv_lib_c_pthread_mutex_init=no
+  ac_cv_lib_pthread_pthread_mutex_init=no
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_c_pthread_mutex_init" >&5
-$as_echo "$ac_cv_lib_c_pthread_mutex_init" >&6; }
-if test "x$ac_cv_lib_c_pthread_mutex_init" = xyes; then :
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_pthread_pthread_mutex_init" >&5
+$as_echo "$ac_cv_lib_pthread_pthread_mutex_init" >&6; }
+if test "x$ac_cv_lib_pthread_pthread_mutex_init" = xyes; then :
   tcl_ok=yes
 else
   tcl_ok=no
 fi
 
-		if test "$tcl_ok" = "no"; then
-		    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for pthread_mutex_init in -lc_r" >&5
-$as_echo_n "checking for pthread_mutex_init in -lc_r... " >&6; }
-if ${ac_cv_lib_c_r_pthread_mutex_init+:} false; then :
+    if test "$tcl_ok" = "no"; then
+	# Check a little harder for __pthread_mutex_init in the same
+	# library, as some systems hide it there until pthread.h is
+	# defined.  We could alternatively do an AC_TRY_COMPILE with
+	# pthread.h, but that will work with libpthread really doesn't
+	# exist, like AIX 4.2.  [Bug: 4359]
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for __pthread_mutex_init in -lpthread" >&5
+$as_echo_n "checking for __pthread_mutex_init in -lpthread... " >&6; }
+if ${ac_cv_lib_pthread___pthread_mutex_init+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lc_r  $LIBS"
+LIBS="-lpthread  $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -4146,217 +4203,91 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 #ifdef __cplusplus
 extern "C"
 #endif
-char pthread_mutex_init ();
+char __pthread_mutex_init ();
 int
 main ()
 {
-return pthread_mutex_init ();
+return __pthread_mutex_init ();
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_c_r_pthread_mutex_init=yes
+  ac_cv_lib_pthread___pthread_mutex_init=yes
 else
-  ac_cv_lib_c_r_pthread_mutex_init=no
+  ac_cv_lib_pthread___pthread_mutex_init=no
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_c_r_pthread_mutex_init" >&5
-$as_echo "$ac_cv_lib_c_r_pthread_mutex_init" >&6; }
-if test "x$ac_cv_lib_c_r_pthread_mutex_init" = xyes; then :
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_pthread___pthread_mutex_init" >&5
+$as_echo "$ac_cv_lib_pthread___pthread_mutex_init" >&6; }
+if test "x$ac_cv_lib_pthread___pthread_mutex_init" = xyes; then :
   tcl_ok=yes
 else
   tcl_ok=no
 fi
 
-		    if test "$tcl_ok" = "yes"; then
-			# The space is needed
-			THREADS_LIBS=" -pthread"
-		    else
-			TCL_THREADS=0
-			{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Don't know how to find pthread lib on your system - you must disable thread support or edit the LIBS in the Makefile..." >&5
-$as_echo "$as_me: WARNING: Don't know how to find pthread lib on your system - you must disable thread support or edit the LIBS in the Makefile..." >&2;}
-		    fi
-		fi
-	    fi
-	fi
-
-	# Does the pthread-implementation provide
-	# 'pthread_attr_setstacksize' ?
-
-	ac_saved_libs=$LIBS
-	LIBS="$LIBS $THREADS_LIBS"
-	for ac_func in pthread_attr_setstacksize pthread_atfork
-do :
-  as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
-ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
-if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
-  cat >>confdefs.h <<_ACEOF
-#define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
-_ACEOF
-
-fi
-done
-
-	LIBS=$ac_saved_libs
-    else
-	TCL_THREADS=0
     fi
-    # Do checking message here to not mess up interleaved configure output
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for building with threads" >&5
-$as_echo_n "checking for building with threads... " >&6; }
-    if test "${TCL_THREADS}" = 1; then
-
-$as_echo "#define TCL_THREADS 1" >>confdefs.h
-
-	if test "${tcl_threaded_core}" = 1; then
-	    { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes (threaded core)" >&5
-$as_echo "yes (threaded core)" >&6; }
-	else
-	    { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-$as_echo "yes" >&6; }
-	fi
-    else
-	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-    fi
-
-
-
-
-#------------------------------------------------------------------------
-# Embedded configuration information, encoding to use for the values, TIP #59
-#------------------------------------------------------------------------
-
-
-
-# Check whether --with-encoding was given.
-if test "${with_encoding+set}" = set; then :
-  withval=$with_encoding; with_tcencoding=${withval}
-fi
-
-
-    if test x"${with_tcencoding}" != x ; then
-
-cat >>confdefs.h <<_ACEOF
-#define TCL_CFGVAL_ENCODING "${with_tcencoding}"
-_ACEOF
 
+    if test "$tcl_ok" = "yes"; then
+	# The space is needed
+	THREADS_LIBS=" -lpthread"
     else
-
-$as_echo "#define TCL_CFGVAL_ENCODING \"iso8859-1\"" >>confdefs.h
-
-    fi
-
-
-#--------------------------------------------------------------------
-# Look for libraries that we will need when compiling the Tcl shell
-#--------------------------------------------------------------------
-
-
-    #--------------------------------------------------------------------
-    # On a few very rare systems, all of the libm.a stuff is
-    # already in libc.a.  Set compiler flags accordingly.
-    #--------------------------------------------------------------------
-
-    ac_fn_c_check_func "$LINENO" "sin" "ac_cv_func_sin"
-if test "x$ac_cv_func_sin" = xyes; then :
-  MATH_LIBS=""
-else
-  MATH_LIBS="-lm"
-fi
-
-
-    #--------------------------------------------------------------------
-    # Interactive UNIX requires -linet instead of -lsocket, plus it
-    # needs net/errno.h to define the socket-related error codes.
-    #--------------------------------------------------------------------
-
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for main in -linet" >&5
-$as_echo_n "checking for main in -linet... " >&6; }
-if ${ac_cv_lib_inet_main+:} false; then :
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for pthread_mutex_init in -lpthreads" >&5
+$as_echo_n "checking for pthread_mutex_init in -lpthreads... " >&6; }
+if ${ac_cv_lib_pthreads_pthread_mutex_init+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-linet  $LIBS"
+LIBS="-lpthreads  $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
-
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char pthread_mutex_init ();
 int
 main ()
 {
-return main ();
+return pthread_mutex_init ();
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_inet_main=yes
+  ac_cv_lib_pthreads_pthread_mutex_init=yes
 else
-  ac_cv_lib_inet_main=no
+  ac_cv_lib_pthreads_pthread_mutex_init=no
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_inet_main" >&5
-$as_echo "$ac_cv_lib_inet_main" >&6; }
-if test "x$ac_cv_lib_inet_main" = xyes; then :
-  LIBS="$LIBS -linet"
-fi
-
-    ac_fn_c_check_header_mongrel "$LINENO" "net/errno.h" "ac_cv_header_net_errno_h" "$ac_includes_default"
-if test "x$ac_cv_header_net_errno_h" = xyes; then :
-
-
-$as_echo "#define HAVE_NET_ERRNO_H 1" >>confdefs.h
-
-fi
-
-
-
-    #--------------------------------------------------------------------
-    #	Check for the existence of the -lsocket and -lnsl libraries.
-    #	The order here is important, so that they end up in the right
-    #	order in the command line generated by make.  Here are some
-    #	special considerations:
-    #	1. Use "connect" and "accept" to check for -lsocket, and
-    #	   "gethostbyname" to check for -lnsl.
-    #	2. Use each function name only once:  can't redo a check because
-    #	   autoconf caches the results of the last check and won't redo it.
-    #	3. Use -lnsl and -lsocket only if they supply procedures that
-    #	   aren't already present in the normal libraries.  This is because
-    #	   IRIX 5.2 has libraries, but they aren't needed and they're
-    #	   bogus:  they goof up name resolution if used.
-    #	4. On some SVR4 systems, can't use -lsocket without -lnsl too.
-    #	   To get around this problem, check for both libraries together
-    #	   if -lsocket doesn't work by itself.
-    #--------------------------------------------------------------------
-
-    tcl_checkBoth=0
-    ac_fn_c_check_func "$LINENO" "connect" "ac_cv_func_connect"
-if test "x$ac_cv_func_connect" = xyes; then :
-  tcl_checkSocket=0
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_pthreads_pthread_mutex_init" >&5
+$as_echo "$ac_cv_lib_pthreads_pthread_mutex_init" >&6; }
+if test "x$ac_cv_lib_pthreads_pthread_mutex_init" = xyes; then :
+  _ok=yes
 else
-  tcl_checkSocket=1
+  tcl_ok=no
 fi
 
-    if test "$tcl_checkSocket" = 1; then
-	ac_fn_c_check_func "$LINENO" "setsockopt" "ac_cv_func_setsockopt"
-if test "x$ac_cv_func_setsockopt" = xyes; then :
-
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for setsockopt in -lsocket" >&5
-$as_echo_n "checking for setsockopt in -lsocket... " >&6; }
-if ${ac_cv_lib_socket_setsockopt+:} false; then :
+	if test "$tcl_ok" = "yes"; then
+	    # The space is needed
+	    THREADS_LIBS=" -lpthreads"
+	else
+	    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for pthread_mutex_init in -lc" >&5
+$as_echo_n "checking for pthread_mutex_init in -lc... " >&6; }
+if ${ac_cv_lib_c_pthread_mutex_init+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lsocket  $LIBS"
+LIBS="-lc  $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -4366,57 +4297,40 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 #ifdef __cplusplus
 extern "C"
 #endif
-char setsockopt ();
+char pthread_mutex_init ();
 int
 main ()
 {
-return setsockopt ();
+return pthread_mutex_init ();
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_socket_setsockopt=yes
+  ac_cv_lib_c_pthread_mutex_init=yes
 else
-  ac_cv_lib_socket_setsockopt=no
+  ac_cv_lib_c_pthread_mutex_init=no
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_socket_setsockopt" >&5
-$as_echo "$ac_cv_lib_socket_setsockopt" >&6; }
-if test "x$ac_cv_lib_socket_setsockopt" = xyes; then :
-  LIBS="$LIBS -lsocket"
-else
-  tcl_checkBoth=1
-fi
-
-fi
-
-    fi
-    if test "$tcl_checkBoth" = 1; then
-	tk_oldLibs=$LIBS
-	LIBS="$LIBS -lsocket -lnsl"
-	ac_fn_c_check_func "$LINENO" "accept" "ac_cv_func_accept"
-if test "x$ac_cv_func_accept" = xyes; then :
-  tcl_checkNsl=0
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_c_pthread_mutex_init" >&5
+$as_echo "$ac_cv_lib_c_pthread_mutex_init" >&6; }
+if test "x$ac_cv_lib_c_pthread_mutex_init" = xyes; then :
+  tcl_ok=yes
 else
-  LIBS=$tk_oldLibs
+  tcl_ok=no
 fi
 
-    fi
-    ac_fn_c_check_func "$LINENO" "gethostbyname" "ac_cv_func_gethostbyname"
-if test "x$ac_cv_func_gethostbyname" = xyes; then :
-
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for gethostbyname in -lnsl" >&5
-$as_echo_n "checking for gethostbyname in -lnsl... " >&6; }
-if ${ac_cv_lib_nsl_gethostbyname+:} false; then :
+	    if test "$tcl_ok" = "no"; then
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for pthread_mutex_init in -lc_r" >&5
+$as_echo_n "checking for pthread_mutex_init in -lc_r... " >&6; }
+if ${ac_cv_lib_c_r_pthread_mutex_init+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lnsl  $LIBS"
+LIBS="-lc_r  $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -4426,32 +4340,61 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 #ifdef __cplusplus
 extern "C"
 #endif
-char gethostbyname ();
+char pthread_mutex_init ();
 int
 main ()
 {
-return gethostbyname ();
+return pthread_mutex_init ();
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_nsl_gethostbyname=yes
+  ac_cv_lib_c_r_pthread_mutex_init=yes
 else
-  ac_cv_lib_nsl_gethostbyname=no
+  ac_cv_lib_c_r_pthread_mutex_init=no
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_nsl_gethostbyname" >&5
-$as_echo "$ac_cv_lib_nsl_gethostbyname" >&6; }
-if test "x$ac_cv_lib_nsl_gethostbyname" = xyes; then :
-  LIBS="$LIBS -lnsl"
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_c_r_pthread_mutex_init" >&5
+$as_echo "$ac_cv_lib_c_r_pthread_mutex_init" >&6; }
+if test "x$ac_cv_lib_c_r_pthread_mutex_init" = xyes; then :
+  tcl_ok=yes
+else
+  tcl_ok=no
 fi
 
+		if test "$tcl_ok" = "yes"; then
+		    # The space is needed
+		    THREADS_LIBS=" -pthread"
+		else
+		    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Don't know how to find pthread lib on your system - you must edit the LIBS in the Makefile..." >&5
+$as_echo "$as_me: WARNING: Don't know how to find pthread lib on your system - you must edit the LIBS in the Makefile..." >&2;}
+		fi
+	    fi
+	fi
+    fi
+
+    # Does the pthread-implementation provide
+    # 'pthread_attr_setstacksize' ?
+
+    ac_saved_libs=$LIBS
+    LIBS="$LIBS $THREADS_LIBS"
+    for ac_func in pthread_attr_setstacksize pthread_atfork
+do :
+  as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
+ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
+if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
+  cat >>confdefs.h <<_ACEOF
+#define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
+_ACEOF
+
 fi
+done
 
+    LIBS=$ac_saved_libs
 
 
 # Add the threads support libraries
diff --git a/unix/configure.ac b/unix/configure.ac
index e14d85e..5b982e8 100644
--- a/unix/configure.ac
+++ b/unix/configure.ac
@@ -120,12 +120,6 @@ if test -z "$no_pipe" && test -n "$GCC"; then
 fi
 
 #------------------------------------------------------------------------
-# Threads support
-#------------------------------------------------------------------------
-
-SC_ENABLE_THREADS
-
-#------------------------------------------------------------------------
 # Embedded configuration information, encoding to use for the values, TIP #59
 #------------------------------------------------------------------------
 
diff --git a/unix/tcl.m4 b/unix/tcl.m4
index 4acbed0..70f3c3d 100644
--- a/unix/tcl.m4
+++ b/unix/tcl.m4
@@ -593,113 +593,6 @@ AC_DEFUN([SC_ENABLE_FRAMEWORK], [
 ])
 
 #------------------------------------------------------------------------
-# SC_ENABLE_THREADS --
-#
-#	Specify if thread support should be enabled
-#
-# Arguments:
-#	none
-#
-# Results:
-#
-#	Adds the following arguments to configure:
-#		--enable-threads
-#
-#	Sets the following vars:
-#		THREADS_LIBS	Thread library(s)
-#
-#	Defines the following vars:
-#		TCL_THREADS
-#		_REENTRANT
-#		_THREAD_SAFE
-#------------------------------------------------------------------------
-
-AC_DEFUN([SC_ENABLE_THREADS], [
-    AC_ARG_ENABLE(threads,
-	AC_HELP_STRING([--enable-threads],
-	    [build with threads (default: on)]),
-	[tcl_ok=$enableval], [tcl_ok=yes])
-
-    if test "${TCL_THREADS}" = 1; then
-	tcl_threaded_core=1;
-    fi
-
-    if test "$tcl_ok" = "yes" -o "${TCL_THREADS}" = 1; then
-	TCL_THREADS=1
-	# USE_THREAD_ALLOC tells us to try the special thread-based
-	# allocator that significantly reduces lock contention
-	AC_DEFINE(USE_THREAD_ALLOC, 1,
-	    [Do we want to use the threaded memory allocator?])
-	AC_DEFINE(_REENTRANT, 1, [Do we want the reentrant OS API?])
-	if test "`uname -s`" = "SunOS" ; then
-	    AC_DEFINE(_POSIX_PTHREAD_SEMANTICS, 1,
-		    [Do we really want to follow the standard? Yes we do!])
-	fi
-	AC_DEFINE(_THREAD_SAFE, 1, [Do we want the thread-safe OS API?])
-	AC_CHECK_LIB(pthread,pthread_mutex_init,tcl_ok=yes,tcl_ok=no)
-	if test "$tcl_ok" = "no"; then
-	    # Check a little harder for __pthread_mutex_init in the same
-	    # library, as some systems hide it there until pthread.h is
-	    # defined.  We could alternatively do an AC_TRY_COMPILE with
-	    # pthread.h, but that will work with libpthread really doesn't
-	    # exist, like AIX 4.2.  [Bug: 4359]
-	    AC_CHECK_LIB(pthread, __pthread_mutex_init,
-		tcl_ok=yes, tcl_ok=no)
-	fi
-
-	if test "$tcl_ok" = "yes"; then
-	    # The space is needed
-	    THREADS_LIBS=" -lpthread"
-	else
-	    AC_CHECK_LIB(pthreads, pthread_mutex_init,
-		tcl_ok=yes, tcl_ok=no)
-	    if test "$tcl_ok" = "yes"; then
-		# The space is needed
-		THREADS_LIBS=" -lpthreads"
-	    else
-		AC_CHECK_LIB(c, pthread_mutex_init,
-		    tcl_ok=yes, tcl_ok=no)
-		if test "$tcl_ok" = "no"; then
-		    AC_CHECK_LIB(c_r, pthread_mutex_init,
-			tcl_ok=yes, tcl_ok=no)
-		    if test "$tcl_ok" = "yes"; then
-			# The space is needed
-			THREADS_LIBS=" -pthread"
-		    else
-			TCL_THREADS=0
-			AC_MSG_WARN([Don't know how to find pthread lib on your system - you must disable thread support or edit the LIBS in the Makefile...])
-		    fi
-		fi
-	    fi
-	fi
-
-	# Does the pthread-implementation provide
-	# 'pthread_attr_setstacksize' ?
-
-	ac_saved_libs=$LIBS
-	LIBS="$LIBS $THREADS_LIBS"
-	AC_CHECK_FUNCS(pthread_attr_setstacksize pthread_atfork)
-	LIBS=$ac_saved_libs
-    else
-	TCL_THREADS=0
-    fi
-    # Do checking message here to not mess up interleaved configure output
-    AC_MSG_CHECKING([for building with threads])
-    if test "${TCL_THREADS}" = 1; then
-	AC_DEFINE(TCL_THREADS, 1, [Are we building with threads enabled?])
-	if test "${tcl_threaded_core}" = 1; then
-	    AC_MSG_RESULT([yes (threaded core)])
-	else
-	    AC_MSG_RESULT([yes])
-	fi
-    else
-	AC_MSG_RESULT([no])
-    fi
-
-    AC_SUBST(TCL_THREADS)
-])
-
-#------------------------------------------------------------------------
 # SC_ENABLE_SYMBOLS --
 #
 #	Specify if debugging symbols should be used.
@@ -2350,13 +2243,21 @@ AC_DEFUN([SC_BUGGY_STRTOD], [
 #
 #	Search for the libraries needed to link the Tcl shell.
 #	Things like the math library (-lm) and socket stuff (-lsocket vs.
-#	-lnsl) are dealt with here.
+#	-lnsl) or thread library (-lpthread) are dealt with here.
 #
 # Arguments:
 #	None.
 #
 # Results:
 #
+#	Sets the following vars:
+#		THREADS_LIBS	Thread library(s)
+#
+#	Defines the following vars:
+#		TCL_THREADS
+#		_REENTRANT
+#		_THREAD_SAFE
+#
 #	Might append to the following vars:
 #		LIBS
 #		MATH_LIBS
@@ -2414,6 +2315,52 @@ AC_DEFUN([SC_TCL_LINK_LIBS], [
     fi
     AC_CHECK_FUNC(gethostbyname, , [AC_CHECK_LIB(nsl, gethostbyname,
 	    [LIBS="$LIBS -lnsl"])])
+
+    AC_DEFINE(_REENTRANT, 1, [Do we want the reentrant OS API?])
+    AC_DEFINE(_THREAD_SAFE, 1, [Do we want the thread-safe OS API?])
+    AC_CHECK_LIB(pthread,pthread_mutex_init,tcl_ok=yes,tcl_ok=no)
+    if test "$tcl_ok" = "no"; then
+	# Check a little harder for __pthread_mutex_init in the same
+	# library, as some systems hide it there until pthread.h is
+	# defined.  We could alternatively do an AC_TRY_COMPILE with
+	# pthread.h, but that will work with libpthread really doesn't
+	# exist, like AIX 4.2.  [Bug: 4359]
+	AC_CHECK_LIB(pthread, __pthread_mutex_init,
+		tcl_ok=yes, tcl_ok=no)
+    fi
+
+    if test "$tcl_ok" = "yes"; then
+	# The space is needed
+	THREADS_LIBS=" -lpthread"
+    else
+	AC_CHECK_LIB(pthreads, pthread_mutex_init,
+	_ok=yes, tcl_ok=no)
+	if test "$tcl_ok" = "yes"; then
+	    # The space is needed
+	    THREADS_LIBS=" -lpthreads"
+	else
+	    AC_CHECK_LIB(c, pthread_mutex_init,
+		    tcl_ok=yes, tcl_ok=no)
+	    if test "$tcl_ok" = "no"; then
+		AC_CHECK_LIB(c_r, pthread_mutex_init,
+			tcl_ok=yes, tcl_ok=no)
+		if test "$tcl_ok" = "yes"; then
+		    # The space is needed
+		    THREADS_LIBS=" -pthread"
+		else
+		    AC_MSG_WARN([Don't know how to find pthread lib on your system - you must edit the LIBS in the Makefile...])
+		fi
+	    fi
+	fi
+    fi
+
+    # Does the pthread-implementation provide
+    # 'pthread_attr_setstacksize' ?
+
+    ac_saved_libs=$LIBS
+    LIBS="$LIBS $THREADS_LIBS"
+    AC_CHECK_FUNCS(pthread_attr_setstacksize pthread_atfork)
+    LIBS=$ac_saved_libs
 ])
 
 #--------------------------------------------------------------------
diff --git a/unix/tclSelectNotfy.c b/unix/tclSelectNotfy.c
index cf21b85..4bdfaef 100644
--- a/unix/tclSelectNotfy.c
+++ b/unix/tclSelectNotfy.c
@@ -81,7 +81,7 @@ typedef struct ThreadSpecificData {
     int numFdBits;		/* Number of valid bits in checkMasks (one
 				 * more than highest fd for which
 				 * Tcl_WatchFile has been called). */
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     int onList;			/* True if it is in this list */
     unsigned int pollState;	/* pollState is used to implement a polling
 				 * handshake between each thread and the
@@ -112,7 +112,7 @@ typedef struct ThreadSpecificData {
 
 static Tcl_ThreadDataKey dataKey;
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /*
  * The following static indicates the number of threads that have initialized
  * notifiers.
@@ -193,7 +193,7 @@ static Tcl_ThreadId notifierThread;
  * Static routines defined in this file.
  */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 static TCL_NORETURN void NotifierThreadProc(ClientData clientData);
 #if defined(HAVE_PTHREAD_ATFORK)
 static int	atForkInit = 0;
@@ -206,7 +206,7 @@ static int	FileHandlerEventProc(Tcl_Event *evPtr, int flags);
  * Import of Windows API when building threaded with Cygwin.
  */
 
-#if defined(TCL_THREADS) && defined(__CYGWIN__)
+#if defined(__CYGWIN__)
 typedef struct {
     void *hwnd;
     unsigned int *message;
@@ -285,7 +285,7 @@ Tcl_InitNotifier(void)
     } else {
 	ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	tsdPtr->eventReady = 0;
 
 	/*
@@ -370,7 +370,7 @@ Tcl_FinalizeNotifier(
 	tclNotifierHooks.finalizeNotifierProc(clientData);
 	return;
     } else {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
 
 	pthread_mutex_lock(&notifierInitMutex);
@@ -587,7 +587,7 @@ Tcl_DeleteFileHandler(
     }
 }
 
-#if defined(TCL_THREADS) && defined(__CYGWIN__)
+#if defined(__CYGWIN__)
 
 static DWORD __stdcall
 NotifierProc(
@@ -640,7 +640,7 @@ Tcl_WaitForEvent(
 	FileHandler *filePtr;
 	int mask;
 	Tcl_Time vTime;
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	int waitForFiles;
 #   ifdef __CYGWIN__
 	MSG msg;
@@ -675,7 +675,7 @@ Tcl_WaitForEvent(
 		tclScaleTimeProcPtr(&vTime, tclTimeClientData);
 		timePtr = &vTime;
 	    }
-#ifndef TCL_THREADS
+#if defined(TCL_THREADS) && !TCL_THREADS
 	    timeout.tv_sec = timePtr->sec;
 	    timeout.tv_usec = timePtr->usec;
 	    timeoutPtr = &timeout;
@@ -694,7 +694,7 @@ Tcl_WaitForEvent(
 #endif /* !TCL_THREADS */
 	}
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	/*
 	 * Start notifier thread and place this thread on the list of
 	 * interested threads, signal the notifier thread, and wait for a
@@ -885,14 +885,14 @@ Tcl_WaitForEvent(
 	    }
 	    filePtr->readyMask = mask;
 	}
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	pthread_mutex_unlock(&notifierMutex);
 #endif /* TCL_THREADS */
 	return 0;
     }
 }
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 
 /*
  *----------------------------------------------------------------------
diff --git a/unix/tclUnixCompat.c b/unix/tclUnixCompat.c
index ea6067e..2d2e53b 100644
--- a/unix/tclUnixCompat.c
+++ b/unix/tclUnixCompat.c
@@ -47,7 +47,7 @@
  * library calls.
  */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 
 typedef struct {
     struct passwd pwd;
@@ -182,7 +182,7 @@ struct passwd *
 TclpGetPwNam(
     const char *name)
 {
-#if !defined(TCL_THREADS)
+#if defined(TCL_THREADS) && !TCL_THREADS
     return getpwnam(name);
 #else
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
@@ -262,7 +262,7 @@ struct passwd *
 TclpGetPwUid(
     uid_t uid)
 {
-#if !defined(TCL_THREADS)
+#if defined(TCL_THREADS) && !TCL_THREADS
     return getpwuid(uid);
 #else
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
@@ -365,7 +365,7 @@ struct group *
 TclpGetGrNam(
     const char *name)
 {
-#if !defined(TCL_THREADS)
+#if defined(TCL_THREADS) && !TCL_THREADS
     return getgrnam(name);
 #else
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
@@ -445,7 +445,7 @@ struct group *
 TclpGetGrGid(
     gid_t gid)
 {
-#if !defined(TCL_THREADS)
+#if defined(TCL_THREADS) && !TCL_THREADS
     return getgrgid(gid);
 #else
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
@@ -548,7 +548,7 @@ struct hostent *
 TclpGetHostByName(
     const char *name)
 {
-#if !defined(TCL_THREADS) || defined(HAVE_MTSAFE_GETHOSTBYNAME)
+#if (defined(TCL_THREADS) && !TCL_THREADS) || defined(HAVE_MTSAFE_GETHOSTBYNAME)
     return gethostbyname(name);
 #else
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
@@ -618,7 +618,7 @@ TclpGetHostByAddr(
     int length,
     int type)
 {
-#if !defined(TCL_THREADS) || defined(HAVE_MTSAFE_GETHOSTBYADDR)
+#if (defined(TCL_THREADS) && !TCL_THREADS) || defined(HAVE_MTSAFE_GETHOSTBYADDR)
     return gethostbyaddr(addr, length, type);
 #else
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
diff --git a/unix/tclUnixFCmd.c b/unix/tclUnixFCmd.c
index 88b9d1c..2b2a613 100644
--- a/unix/tclUnixFCmd.c
+++ b/unix/tclUnixFCmd.c
@@ -256,7 +256,7 @@ Realpath(
 #endif /* PURIFY */
 
 #ifndef NO_REALPATH
-#if defined(__APPLE__) && defined(TCL_THREADS) && \
+#if defined(__APPLE__) && (!defined(TCL_THREADS) || TCL_THREADS) && \
 	defined(MAC_OS_X_VERSION_MIN_REQUIRED) && \
 	MAC_OS_X_VERSION_MIN_REQUIRED < 1030
 /*
diff --git a/unix/tclUnixInit.c b/unix/tclUnixInit.c
index 630460a..78d591a 100644
--- a/unix/tclUnixInit.c
+++ b/unix/tclUnixInit.c
@@ -316,7 +316,7 @@ static int		MacOSXGetLibraryPath(Tcl_Interp *interp,
 #endif /* HAVE_COREFOUNDATION */
 #if defined(__APPLE__) && (defined(TCL_LOAD_FROM_MEMORY) || ( \
 	defined(MAC_OS_X_VERSION_MIN_REQUIRED) && ( \
-	(defined(TCL_THREADS) && MAC_OS_X_VERSION_MIN_REQUIRED < 1030) || \
+	((!defined(TCL_THREADS) || TCL_THREADS) && MAC_OS_X_VERSION_MIN_REQUIRED < 1030) || \
 	(defined(__LP64__) && MAC_OS_X_VERSION_MIN_REQUIRED < 1050) || \
 	(defined(HAVE_COREFOUNDATION) && MAC_OS_X_VERSION_MIN_REQUIRED < 1050)\
 	)))
diff --git a/unix/tclUnixNotfy.c b/unix/tclUnixNotfy.c
index b7df740..ccae39b 100644
--- a/unix/tclUnixNotfy.c
+++ b/unix/tclUnixNotfy.c
@@ -18,7 +18,7 @@
  */
 
 #ifdef NOTIFIER_SELECT
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 static TCL_NORETURN void NotifierThreadProc(ClientData clientData);
 #if defined(HAVE_PTHREAD_ATFORK)
 static void	AtForkChild(void);
@@ -28,7 +28,7 @@ static void	AtForkChild(void);
 static int	FileHandlerEventProc(Tcl_Event *evPtr, int flags);
 
 #ifdef NOTIFIER_SELECT
-#if TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /*
  *----------------------------------------------------------------------
  *
@@ -107,7 +107,7 @@ Tcl_AlertNotifier(
 	return;
     } else {
 #ifdef NOTIFIER_SELECT
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	ThreadSpecificData *tsdPtr = clientData;
 
 	pthread_mutex_lock(&notifierMutex);
@@ -198,7 +198,7 @@ Tcl_ServiceModeHook(
 	return;
     } else if (mode == TCL_SERVICE_ALL) {
 #ifdef NOTIFIER_SELECT
-#if TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 	StartNotifierThread("Tcl_ServiceModeHook");
 #endif
 #endif /* NOTIFIER_SELECT */
@@ -280,7 +280,7 @@ FileHandlerEventProc(
 }
 
 #ifdef NOTIFIER_SELECT
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /*
  *----------------------------------------------------------------------
  *
diff --git a/unix/tclUnixPort.h b/unix/tclUnixPort.h
index fec27d0..e4277a3 100644
--- a/unix/tclUnixPort.h
+++ b/unix/tclUnixPort.h
@@ -610,10 +610,8 @@ extern char **		environ;
 #	    undef HAVE_COPYFILE
 #	endif
 #	if MAC_OS_X_VERSION_MAX_ALLOWED < 1030
-#	    ifdef TCL_THREADS
-		/* prior to 10.3, realpath is not threadsafe, c.f. bug 711232 */
-#		define NO_REALPATH 1
-#	    endif
+	    /* prior to 10.3, realpath is not threadsafe, c.f. bug 711232 */
+#	    define NO_REALPATH 1
 #	    undef HAVE_LANGINFO
 #	endif
 #   endif /* MAC_OS_X_VERSION_MAX_ALLOWED */
@@ -686,7 +684,7 @@ typedef int socklen_t;
 
 #define TclpExit	exit
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 #   include <pthread.h>
 #endif /* TCL_THREADS */
 
diff --git a/unix/tclUnixThrd.c b/unix/tclUnixThrd.c
index 120d5d5..76228a3 100644
--- a/unix/tclUnixThrd.c
+++ b/unix/tclUnixThrd.c
@@ -13,7 +13,7 @@
 
 #include "tclInt.h"
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 
 #ifndef TCL_NO_DEPRECATED
 typedef struct {
@@ -74,7 +74,7 @@ TclpThreadCreate(
     int flags)			/* Flags controlling behaviour of the new
 				 * thread. */
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     pthread_attr_t attr;
     pthread_t theThread;
     int result;
@@ -152,7 +152,7 @@ Tcl_JoinThread(
 				 * thread we wait upon will be written into.
 				 * May be NULL. */
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     int result;
     unsigned long retcode, *retcodePtr = &retcode;
 
@@ -166,7 +166,7 @@ Tcl_JoinThread(
 #endif
 }
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /*
  *----------------------------------------------------------------------
  *
@@ -210,7 +210,7 @@ TclpThreadExit(
 Tcl_ThreadId
 Tcl_GetCurrentThread(void)
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     return (Tcl_ThreadId) pthread_self();
 #else
     return (Tcl_ThreadId) 0;
@@ -239,7 +239,7 @@ Tcl_GetCurrentThread(void)
 void
 TclpInitLock(void)
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     pthread_mutex_lock(&initLock);
 #endif
 }
@@ -265,7 +265,7 @@ TclpInitLock(void)
 void
 TclFinalizeLock(void)
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     /*
      * You do not need to destroy mutexes that were created with the
      * PTHREAD_MUTEX_INITIALIZER macro. These mutexes do not need any
@@ -296,7 +296,7 @@ TclFinalizeLock(void)
 void
 TclpInitUnlock(void)
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     pthread_mutex_unlock(&initLock);
 #endif
 }
@@ -325,7 +325,7 @@ TclpInitUnlock(void)
 void
 TclpMasterLock(void)
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     pthread_mutex_lock(&masterLock);
 #endif
 }
@@ -351,7 +351,7 @@ TclpMasterLock(void)
 void
 TclpMasterUnlock(void)
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     pthread_mutex_unlock(&masterLock);
 #endif
 }
@@ -378,7 +378,7 @@ TclpMasterUnlock(void)
 Tcl_Mutex *
 Tcl_GetAllocMutex(void)
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     pthread_mutex_t **allocLockPtrPtr = &allocLockPtr;
     return (Tcl_Mutex *) allocLockPtrPtr;
 #else
@@ -386,7 +386,7 @@ Tcl_GetAllocMutex(void)
 #endif
 }
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 
 /*
  *----------------------------------------------------------------------
@@ -659,7 +659,7 @@ char *
 TclpInetNtoa(
     struct in_addr addr)
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
     unsigned char *b = (unsigned char*) &addr.s_addr;
 
@@ -671,7 +671,7 @@ TclpInetNtoa(
 }
 #endif /* TCL_NO_DEPRECATED */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 /*
  * Additions by AOL for specialized thread memory allocator.
  */
diff --git a/unix/tclUnixThrd.h b/unix/tclUnixThrd.h
deleted file mode 100644
index f03b530..0000000
--- a/unix/tclUnixThrd.h
+++ /dev/null
@@ -1,19 +0,0 @@
-/*
- * tclUnixThrd.h --
- *
- *      This header file defines things for thread support.
- *
- * Copyright (c) 1998 Sun Microsystems, Inc.
- *
- * See the file "license.terms" for information on usage and redistribution
- * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
- */
-
-#ifndef _TCLUNIXTHRD
-#define _TCLUNIXTHRD
-
-#ifdef TCL_THREADS
-
-
-#endif /* TCL_THREADS */
-#endif /* _TCLUNIXTHRD */
diff --git a/win/configure b/win/configure
index 59bc5de..7ab33b0 100755
--- a/win/configure
+++ b/win/configure
@@ -707,7 +707,6 @@ CFLAGS_OPTIMIZE
 CFLAGS_DEBUG
 DL_LIBS
 CYGPATH
-TCL_THREADS
 SET_MAKE
 RC
 RANLIB
@@ -763,7 +762,6 @@ SHELL'
 ac_subst_files=''
 ac_user_opts='
 enable_option_checking
-enable_threads
 with_encoding
 enable_shared
 enable_64bit
@@ -1386,7 +1384,6 @@ Optional Features:
   --disable-option-checking  ignore unrecognized --enable/--with options
   --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
   --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
-  --enable-threads        build with threads (default: on)
   --enable-shared         build and link with shared libraries (default: on)
   --enable-64bit          enable 64bit support (where applicable)
   --enable-symbols        build with debugging symbols (default: off)
@@ -3673,39 +3670,6 @@ fi
 
 
 
-#--------------------------------------------------------------------
-# Check whether --enable-threads or --disable-threads was given.
-#--------------------------------------------------------------------
-
-
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for building with threads" >&5
-$as_echo_n "checking for building with threads... " >&6; }
-    # Check whether --enable-threads was given.
-if test "${enable_threads+set}" = set; then :
-  enableval=$enable_threads; tcl_ok=$enableval
-else
-  tcl_ok=yes
-fi
-
-
-    if test "$tcl_ok" = "yes"; then
-	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes (default)" >&5
-$as_echo "yes (default)" >&6; }
-	TCL_THREADS=1
-	$as_echo "#define TCL_THREADS 1" >>confdefs.h
-
-	# USE_THREAD_ALLOC tells us to try the special thread-based
-	# allocator that significantly reduces lock contention
-	$as_echo "#define USE_THREAD_ALLOC 1" >>confdefs.h
-
-    else
-	TCL_THREADS=0
-	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-    fi
-
-
-
 #------------------------------------------------------------------------
 # Embedded configuration information, encoding to use for the values, TIP #59
 #------------------------------------------------------------------------
diff --git a/win/configure.ac b/win/configure.ac
index d03695c..179f151 100644
--- a/win/configure.ac
+++ b/win/configure.ac
@@ -78,12 +78,6 @@ AC_PROG_MAKE_SET
 AC_OBJEXT
 AC_EXEEXT
 
-#--------------------------------------------------------------------
-# Check whether --enable-threads or --disable-threads was given.
-#--------------------------------------------------------------------
-
-SC_ENABLE_THREADS
-
 #------------------------------------------------------------------------
 # Embedded configuration information, encoding to use for the values, TIP #59
 #------------------------------------------------------------------------
diff --git a/win/rules.vc b/win/rules.vc
index 13b3fba..f93400c 100644
--- a/win/rules.vc
+++ b/win/rules.vc
@@ -730,15 +730,6 @@ TCL_USE_STATIC_PACKAGES	= 1
 TCL_USE_STATIC_PACKAGES	= 0

 !endif

 

-!if [nmakehlp -f $(OPTS) "nothreads"]

-!message *** Compile explicitly for non-threaded tcl

-TCL_THREADS	= 0

-USE_THREAD_ALLOC= 0

-!else

-TCL_THREADS	= 1

-USE_THREAD_ALLOC= 1

-!endif

-

 !if [nmakehlp -f $(OPTS) "symbols"]

 !message *** Doing symbols

 DEBUG		= 1

@@ -774,12 +765,6 @@ PGO		= 0
 !message *** Warning: ignoring option "loimpact" - deprecated on modern Windows.

 !endif

 

-# TBD - should get rid of this option

-!if [nmakehlp -f $(OPTS) "thrdalloc"]

-!message *** Doing thrdalloc

-USE_THREAD_ALLOC = 1

-!endif

-

 !if [nmakehlp -f $(OPTS) "tclalloc"]

 USE_THREAD_ALLOC = 0

 !endif

@@ -970,7 +955,7 @@ VERSION         = $(DOTVERSION:.=)
 # different compilers, build configurations etc.,

 #

 # Naming convention (suffixes):

-#   t = full thread support.

+#   t = full thread support. (Not used for Tcl >= 8.7)

 #   s = static library (as opposed to an import library)

 #   g = linked to the debug enabled C run-time.

 #   x = special static build when it links to the dynamic C run-time.

@@ -1028,7 +1013,7 @@ SUFX	    = $(SUFX:x=)
 !endif

 !endif

 

-!if !$(TCL_THREADS)

+!if !$(TCL_THREADS) || $(TCL_VERSION) > 86

 TMP_DIRFULL = $(TMP_DIRFULL:Threaded=)

 SUFX	    = $(SUFX:t=)

 !endif

@@ -1079,9 +1064,6 @@ TCL_INCLUDES    = -I"$(WINDIR)" -I"$(GENERICDIR)"
 # of Tcl we are building against, this may or may not have a "t" suffix.

 # Try various possibilities in turn.

 TCLSH		= $(_TCLDIR)\bin\tclsh$(TCL_VERSION)$(SUFX).exe

-!if !exist("$(TCLSH)") && $(TCL_THREADS)

-TCLSH           = $(_TCLDIR)\bin\tclsh$(TCL_VERSION)t$(SUFX).exe

-!endif

 !if !exist("$(TCLSH)")

 TCLSH           = $(_TCLDIR)\bin\tclsh$(TCL_VERSION)$(SUFX:t=).exe

 !endif

@@ -1102,9 +1084,6 @@ TCL_INCLUDES    = -I"$(_TCLDIR)\include"
 !else # Building against Tcl sources

 

 TCLSH		= $(_TCLDIR)\win\$(BUILDDIRTOP)\tclsh$(TCL_VERSION)$(SUFX).exe

-!if !exist($(TCLSH)) && $(TCL_THREADS)

-TCLSH		= $(_TCLDIR)\win\$(BUILDDIRTOP)\tclsh$(TCL_VERSION)t$(SUFX).exe

-!endif

 !if !exist($(TCLSH))

 TCLSH		= $(_TCLDIR)\win\$(BUILDDIRTOP)\tclsh$(TCL_VERSION)$(SUFX:t=).exe

 !endif

@@ -1264,7 +1243,7 @@ OPTDEFINES	= $(OPTDEFINES) -DTCL_MEM_DEBUG
 !if $(TCL_COMPILE_DEBUG)

 OPTDEFINES	= $(OPTDEFINES) -DTCL_COMPILE_DEBUG -DTCL_COMPILE_STATS

 !endif

-!if $(TCL_THREADS)

+!if $(TCL_THREADS) && $(TCL_VERSION) < 86

 OPTDEFINES	= $(OPTDEFINES) -DTCL_THREADS=1

 !if $(USE_THREAD_ALLOC)

 OPTDEFINES	= $(OPTDEFINES) -DUSE_THREAD_ALLOC=1

@@ -1708,9 +1687,6 @@ TCLNMAKECONFIG = "$(OUT_DIR)\tcl.nmake"
 !if defined(CORE_MACHINE) && "$(CORE_MACHINE)" != "$(MACHINE)"

 !error ERROR: Build target ($(MACHINE)) does not match the Tcl library architecture ($(CORE_MACHINE)).

 !endif

-!if defined(CORE_USE_THREAD_ALLOC) && $(CORE_USE_THREAD_ALLOC) != $(USE_THREAD_ALLOC)

-!message WARNING: Value of USE_THREAD_ALLOC ($(USE_THREAD_ALLOC)) does not match its Tcl core value ($(CORE_USE_THREAD_ALLOC)).

-!endif

 !if defined(CORE_DEBUG) && $(CORE_DEBUG) != $(DEBUG)

 !message WARNING: Value of DEBUG ($(DEBUG)) does not match its Tcl library configuration ($(DEBUG)).

 !endif

diff --git a/win/tcl.m4 b/win/tcl.m4
index 0e4a3a5..e2a2fb2 100644
--- a/win/tcl.m4
+++ b/win/tcl.m4
@@ -383,42 +383,6 @@ AC_DEFUN([SC_ENABLE_SHARED], [
 ])
 
 #------------------------------------------------------------------------
-# SC_ENABLE_THREADS --
-#
-#	Specify if thread support should be enabled
-#
-# Arguments:
-#	none
-#
-# Results:
-#
-#	Adds the following arguments to configure:
-#		--enable-threads=yes|no
-#
-#	Defines the following vars:
-#		TCL_THREADS
-#------------------------------------------------------------------------
-
-AC_DEFUN([SC_ENABLE_THREADS], [
-    AC_MSG_CHECKING(for building with threads)
-    AC_ARG_ENABLE(threads, [  --enable-threads        build with threads (default: on)],
-	[tcl_ok=$enableval], [tcl_ok=yes])
-
-    if test "$tcl_ok" = "yes"; then
-	AC_MSG_RESULT([yes (default)])
-	TCL_THREADS=1
-	AC_DEFINE(TCL_THREADS)
-	# USE_THREAD_ALLOC tells us to try the special thread-based
-	# allocator that significantly reduces lock contention
-	AC_DEFINE(USE_THREAD_ALLOC)
-    else
-	TCL_THREADS=0
-	AC_MSG_RESULT(no)
-    fi
-    AC_SUBST(TCL_THREADS)
-])
-
-#------------------------------------------------------------------------
 # SC_ENABLE_SYMBOLS --
 #
 #	Specify if debugging symbols should be used.
diff --git a/win/tcl.rc b/win/tcl.rc
index be5e0a7..477512d 100644
--- a/win/tcl.rc
+++ b/win/tcl.rc
@@ -7,19 +7,13 @@
 //
 // build-up the name suffix that defines the type of build this is.
 //
-#if TCL_THREADS
-#define SUFFIX_THREADS	    "t"
-#else
-#define SUFFIX_THREADS	    ""
-#endif
-
 #if DEBUG && !UNCHECKED
 #define SUFFIX_DEBUG	    "g"
 #else
 #define SUFFIX_DEBUG	    ""
 #endif
 
-#define SUFFIX		    SUFFIX_THREADS SUFFIX_DEBUG
+#define SUFFIX		    SUFFIX_DEBUG
 
 
 LANGUAGE 0x9, 0x1	/* LANG_ENGLISH, SUBLANG_DEFAULT */
diff --git a/win/tclWinInt.h b/win/tclWinInt.h
index 08d80fb..a1ccb36 100644
--- a/win/tclWinInt.h
+++ b/win/tclWinInt.h
@@ -63,13 +63,6 @@ MODULE_SCOPE int	TclWinSymLinkCopyDirectory(const TCHAR *LinkOriginal,
 MODULE_SCOPE int	TclWinSymLinkDelete(const TCHAR *LinkOriginal,
 			    int linkOnly);
 MODULE_SCOPE int        TclWinFileOwned(Tcl_Obj *);
-#if defined(TCL_THREADS) && defined(USE_THREAD_ALLOC)
-MODULE_SCOPE void	TclWinFreeAllocCache(void);
-MODULE_SCOPE void	TclFreeAllocCache(void *);
-MODULE_SCOPE Tcl_Mutex *TclpNewAllocMutex(void);
-MODULE_SCOPE void *	TclpGetAllocCache(void);
-MODULE_SCOPE void	TclpSetAllocCache(void *);
-#endif /* TCL_THREADS */
 
 /* Needed by tclWinFile.c and tclWinFCmd.c */
 #ifndef FILE_ATTRIBUTE_REPARSE_POINT
diff --git a/win/tclWinThrd.c b/win/tclWinThrd.c
index 8c130a7..07b6db9 100644
--- a/win/tclWinThrd.c
+++ b/win/tclWinThrd.c
@@ -41,7 +41,7 @@ static CRITICAL_SECTION initLock;
  * obvious reasons, cannot use any dyamically allocated storage.
  */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 
 static struct Tcl_Mutex_ {
     CRITICAL_SECTION crit;
@@ -76,7 +76,7 @@ static CRITICAL_SECTION joinLock;
  * The per-thread event and queue pointers.
  */
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 
 typedef struct ThreadSpecificData {
     HANDLE condEvent;			/* Per-thread condition event */
@@ -474,7 +474,7 @@ TclpMasterUnlock(void)
 Tcl_Mutex *
 Tcl_GetAllocMutex(void)
 {
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (!allocOnce) {
 	InitializeCriticalSection(&allocLock.crit);
 	allocOnce = 1;
@@ -516,7 +516,7 @@ TclFinalizeLock(void)
     DeleteCriticalSection(&masterLock);
     initialized = 0;
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
     if (allocOnce) {
 	DeleteCriticalSection(&allocLock.crit);
 	allocOnce = 0;
@@ -532,7 +532,7 @@ TclFinalizeLock(void)
     DeleteCriticalSection(&initLock);
 }
 
-#ifdef TCL_THREADS
+#if !defined(TCL_THREADS) || TCL_THREADS
 
 /* locally used prototype */
 static void		FinalizeConditionEvent(ClientData data);
diff --git a/win/tclsh.rc b/win/tclsh.rc
index 161da50..bd1a4da 100644
--- a/win/tclsh.rc
+++ b/win/tclsh.rc
@@ -8,12 +8,6 @@
 //
 // build-up the name suffix that defines the type of build this is.
 //
-#if TCL_THREADS
-#define SUFFIX_THREADS	    "t"
-#else
-#define SUFFIX_THREADS	    ""
-#endif
-
 #if STATIC_BUILD
 #define SUFFIX_STATIC	    "s"
 #else
@@ -26,7 +20,7 @@
 #define SUFFIX_DEBUG	    ""
 #endif
 
-#define SUFFIX		    SUFFIX_THREADS SUFFIX_STATIC SUFFIX_DEBUG
+#define SUFFIX		    SUFFIX_STATIC SUFFIX_DEBUG
 
 
 LANGUAGE 0x9, 0x1	/* LANG_ENGLISH, SUBLANG_DEFAULT */