Merge trunk

9 files changed, 294 insertions, 88 deletions

diff --git a/unix/Makefile.in b/unix/Makefile.in
index d35074e..2068c86 100644
--- a/unix/Makefile.in
+++ b/unix/Makefile.in
@@ -396,8 +396,7 @@ GENERIC_HDRS = \
 	$(GENERIC_DIR)/tclPatch.h \
 	$(GENERIC_DIR)/tclPlatDecls.h \
 	$(GENERIC_DIR)/tclPort.h \
-	$(GENERIC_DIR)/tclRegexp.h \
-	$(GENERIC_DIR)/tclArithSeries.h
+	$(GENERIC_DIR)/tclRegexp.h
 
 GENERIC_SRCS = \
 	$(GENERIC_DIR)/regcomp.c \
diff --git a/unix/configure b/unix/configure
index 3f93ef3..c0a5575 100755
--- a/unix/configure
+++ b/unix/configure
@@ -737,6 +737,8 @@ RANLIB
 TOMMATH_INCLUDE
 TOMMATH_SRCS
 TOMMATH_OBJS
+TCL_PC_CFLAGS
+TCL_PC_REQUIRES_PRIVATE
 ZLIB_INCLUDE
 ZLIB_SRCS
 ZLIB_OBJS
@@ -5139,6 +5141,10 @@ fi
 if test $libtommath_ok = yes
 then :
 
+  TCL_PC_REQUIRES_PRIVATE='libtommath >= 1.2.0,'
+
+  TCL_PC_CFLAGS='-DTCL_WITH_EXTERNAL_TOMMATH'
+
 
 printf "%s\n" "#define TCL_WITH_EXTERNAL_TOMMATH 1" >>confdefs.h
 
@@ -7323,6 +7329,33 @@ printf "%s\n" "#define HAVE_STDBOOL_H 1" >>confdefs.h
 fi
 
 
+    # Check for vfork, posix_spawnp() and friends unconditionally
+    ac_fn_c_check_func "$LINENO" "vfork" "ac_cv_func_vfork"
+if test "x$ac_cv_func_vfork" = xyes
+then :
+  printf "%s\n" "#define HAVE_VFORK 1" >>confdefs.h
+
+fi
+ac_fn_c_check_func "$LINENO" "posix_spawnp" "ac_cv_func_posix_spawnp"
+if test "x$ac_cv_func_posix_spawnp" = xyes
+then :
+  printf "%s\n" "#define HAVE_POSIX_SPAWNP 1" >>confdefs.h
+
+fi
+ac_fn_c_check_func "$LINENO" "posix_spawn_file_actions_adddup2" "ac_cv_func_posix_spawn_file_actions_adddup2"
+if test "x$ac_cv_func_posix_spawn_file_actions_adddup2" = xyes
+then :
+  printf "%s\n" "#define HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2 1" >>confdefs.h
+
+fi
+ac_fn_c_check_func "$LINENO" "posix_spawnattr_setflags" "ac_cv_func_posix_spawnattr_setflags"
+if test "x$ac_cv_func_posix_spawnattr_setflags" = xyes
+then :
+  printf "%s\n" "#define HAVE_POSIX_SPAWNATTR_SETFLAGS 1" >>confdefs.h
+
+fi
+
+
     # FIXME: This subst was left in only because the TCL_DL_LIBS
     # entry in tclConfig.sh uses it. It is not clear why someone
     # would use TCL_DL_LIBS instead of TCL_LIBS.
@@ -7486,6 +7519,56 @@ printf "%s\n" "#define _ISOC99_SOURCE 1" >>confdefs.h
     fi
 
 
+    if test ${tcl_cv_flag__file_offset_bits+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/stat.h>
+int
+main (void)
+{
+switch (0) { case 0: case (sizeof(off_t)==sizeof(long long)): ; }
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  tcl_cv_flag__file_offset_bits=no
+else $as_nop
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#define _FILE_OFFSET_BITS 64
+#include <sys/stat.h>
+int
+main (void)
+{
+switch (0) { case 0: case (sizeof(off_t)==sizeof(long long)): ; }
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  tcl_cv_flag__file_offset_bits=yes
+else $as_nop
+  tcl_cv_flag__file_offset_bits=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+    if test "x${tcl_cv_flag__file_offset_bits}" = "xyes" ; then
+
+printf "%s\n" "#define _FILE_OFFSET_BITS 64" >>confdefs.h
+
+	tcl_flags="$tcl_flags _FILE_OFFSET_BITS"
+    fi
+
+
     if test ${tcl_cv_flag__largefile64_source+y}
 then :
   printf %s "(cached) " >&6
@@ -7586,9 +7669,9 @@ printf "%s\n" "yes" >&6; }
 	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
 printf "%s\n" "no" >&6; }
 	# Now check for auxiliary declarations
-	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for struct dirent64" >&5
-printf %s "checking for struct dirent64... " >&6; }
-if test ${tcl_cv_struct_dirent64+y}
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for 64-bit time_t" >&5
+printf %s "checking for 64-bit time_t... " >&6; }
+if test ${tcl_cv_time_t_64+y}
 then :
   printf %s "(cached) " >&6
 else $as_nop
@@ -7596,34 +7679,66 @@ else $as_nop
 	    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <sys/types.h>
-#include <dirent.h>
 int
 main (void)
 {
-struct dirent64 p;
+switch (0) {case 0: case (sizeof(time_t)==sizeof(long long)): ;}
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"
 then :
-  tcl_cv_struct_dirent64=yes
+  tcl_cv_time_t_64=yes
 else $as_nop
-  tcl_cv_struct_dirent64=no
+  tcl_cv_time_t_64=no
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
 fi
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $tcl_cv_struct_dirent64" >&5
-printf "%s\n" "$tcl_cv_struct_dirent64" >&6; }
-	if test "x${tcl_cv_struct_dirent64}" = "xyes" ; then
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $tcl_cv_time_t_64" >&5
+printf "%s\n" "$tcl_cv_time_t_64" >&6; }
+	if test "x${tcl_cv_time_t_64}" = "xno" ; then
+	    # Note that _TIME_BITS=64 requires _FILE_OFFSET_BITS=64
+	    # which SC_TCL_EARLY_FLAGS has defined if necessary.
+	    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if _TIME_BITS=64 enables 64-bit time_t" >&5
+printf %s "checking if _TIME_BITS=64 enables 64-bit time_t... " >&6; }
+if test ${tcl_cv__time_bits+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
 
-printf "%s\n" "#define HAVE_STRUCT_DIRENT64 1" >>confdefs.h
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#define _TIME_BITS 64
+#include <sys/types.h>
+int
+main (void)
+{
+switch (0) {case 0: case (sizeof(time_t)==sizeof(long long)): ;}
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  tcl_cv__time_bits=yes
+else $as_nop
+  tcl_cv__time_bits=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $tcl_cv__time_bits" >&5
+printf "%s\n" "$tcl_cv__time_bits" >&6; }
+	    if test "x${tcl_cv__time_bits}" = "xyes" ; then
+
+printf "%s\n" "#define _TIME_BITS 64" >>confdefs.h
 
+	    fi
 	fi
 
-	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for DIR64" >&5
-printf %s "checking for DIR64... " >&6; }
-if test ${tcl_cv_DIR64+y}
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for struct dirent64" >&5
+printf %s "checking for struct dirent64... " >&6; }
+if test ${tcl_cv_struct_dirent64+y}
 then :
   printf %s "(cached) " >&6
 else $as_nop
@@ -7635,60 +7750,60 @@ else $as_nop
 int
 main (void)
 {
-struct dirent64 *p; DIR64 d = opendir64(".");
-            p = readdir64(d); rewinddir64(d); closedir64(d);
+struct dirent64 p;
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"
 then :
-  tcl_cv_DIR64=yes
+  tcl_cv_struct_dirent64=yes
 else $as_nop
-  tcl_cv_DIR64=no
+  tcl_cv_struct_dirent64=no
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
 fi
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $tcl_cv_DIR64" >&5
-printf "%s\n" "$tcl_cv_DIR64" >&6; }
-	if test "x${tcl_cv_DIR64}" = "xyes" ; then
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $tcl_cv_struct_dirent64" >&5
+printf "%s\n" "$tcl_cv_struct_dirent64" >&6; }
+	if test "x${tcl_cv_struct_dirent64}" = "xyes" ; then
 
-printf "%s\n" "#define HAVE_DIR64 1" >>confdefs.h
+printf "%s\n" "#define HAVE_STRUCT_DIRENT64 1" >>confdefs.h
 
 	fi
 
-	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for struct stat64" >&5
-printf %s "checking for struct stat64... " >&6; }
-if test ${tcl_cv_struct_stat64+y}
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for DIR64" >&5
+printf %s "checking for DIR64... " >&6; }
+if test ${tcl_cv_DIR64+y}
 then :
   printf %s "(cached) " >&6
 else $as_nop
 
 	    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#include <sys/stat.h>
+#include <sys/types.h>
+#include <dirent.h>
 int
 main (void)
 {
-struct stat64 p;
-
+struct dirent64 *p; DIR64 d = opendir64(".");
+            p = readdir64(d); rewinddir64(d); closedir64(d);
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"
 then :
-  tcl_cv_struct_stat64=yes
+  tcl_cv_DIR64=yes
 else $as_nop
-  tcl_cv_struct_stat64=no
+  tcl_cv_DIR64=no
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
 fi
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $tcl_cv_struct_stat64" >&5
-printf "%s\n" "$tcl_cv_struct_stat64" >&6; }
-	if test "x${tcl_cv_struct_stat64}" = "xyes" ; then
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $tcl_cv_DIR64" >&5
+printf "%s\n" "$tcl_cv_DIR64" >&6; }
+	if test "x${tcl_cv_DIR64}" = "xyes" ; then
 
-printf "%s\n" "#define HAVE_STRUCT_STAT64 1" >>confdefs.h
+printf "%s\n" "#define HAVE_DIR64 1" >>confdefs.h
 
 	fi
 
@@ -10072,9 +10187,6 @@ fi
 
     fi
 
-printf "%s\n" "#define USE_VFORK 1" >>confdefs.h
-
-
 printf "%s\n" "#define TCL_LOAD_FROM_MEMORY 1" >>confdefs.h
 
 
diff --git a/unix/configure.ac b/unix/configure.ac
index f7538c3..633b568 100644
--- a/unix/configure.ac
+++ b/unix/configure.ac
@@ -185,6 +185,8 @@ if test x"${libtommath_ok}" = x -o x"${libtommath_ok}" != xno; then
     libtommath_ok=no])])
 fi
 AS_IF([test $libtommath_ok = yes], [
+  AC_SUBST(TCL_PC_REQUIRES_PRIVATE, ['libtommath >= 1.2.0,'])
+  AC_SUBST(TCL_PC_CFLAGS, ['-DTCL_WITH_EXTERNAL_TOMMATH'])
   AC_DEFINE(TCL_WITH_EXTERNAL_TOMMATH, 1, [Tcl with external libtommath])
 ], [
   AC_SUBST(TOMMATH_OBJS,[\${TOMMATH_OBJS}])
@@ -540,7 +542,6 @@ if test "`uname -s`" = "Darwin" ; then
 	AC_CHECK_HEADERS(libkern/OSAtomic.h)
 	AC_CHECK_FUNCS(OSSpinLockLock)
     fi
-    AC_DEFINE(USE_VFORK, 1, [Should we use vfork() instead of fork()?])
     AC_DEFINE(TCL_LOAD_FROM_MEMORY, 1,
 	[Can this platform load code from memory?])
     AC_DEFINE(TCL_WIDE_CLICKS, 1,
diff --git a/unix/tcl.m4 b/unix/tcl.m4
index 9dc39f2..fca47cc 100644
--- a/unix/tcl.m4
+++ b/unix/tcl.m4
@@ -1877,6 +1877,9 @@ dnl # preprocessing tests use only CPPFLAGS.
 
     AC_CHECK_HEADER(stdbool.h, [AC_DEFINE(HAVE_STDBOOL_H, 1, [Do we have <stdbool.h>?])],)
 
+    # Check for vfork, posix_spawnp() and friends unconditionally
+    AC_CHECK_FUNCS(vfork posix_spawnp posix_spawn_file_actions_adddup2 posix_spawnattr_setflags)
+
     # FIXME: This subst was left in only because the TCL_DL_LIBS
     # entry in tclConfig.sh uses it. It is not clear why someone
     # would use TCL_DL_LIBS instead of TCL_LIBS.
@@ -2294,6 +2297,7 @@ AC_DEFUN([SC_TCL_LINK_LIBS], [
 #
 #	Might define the following vars:
 #		_ISOC99_SOURCE
+#		_FILE_OFFSET_BITS
 #		_LARGEFILE64_SOURCE
 #
 #--------------------------------------------------------------------
@@ -2301,12 +2305,12 @@ AC_DEFUN([SC_TCL_LINK_LIBS], [
 AC_DEFUN([SC_TCL_EARLY_FLAG],[
     AC_CACHE_VAL([tcl_cv_flag_]translit($1,[A-Z],[a-z]),
 	AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[$2]], [[$3]])],
-	    [tcl_cv_flag_]translit($1,[A-Z],[a-z])=no,[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[[#define ]$1[ 1
+	    [tcl_cv_flag_]translit($1,[A-Z],[a-z])=no,[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[[#define ]$1[ ]m4_default([$4],[1])[
 ]$2]], [[$3]])],
 	[tcl_cv_flag_]translit($1,[A-Z],[a-z])=yes,
 	[tcl_cv_flag_]translit($1,[A-Z],[a-z])=no)]))
     if test ["x${tcl_cv_flag_]translit($1,[A-Z],[a-z])[}" = "xyes"] ; then
-	AC_DEFINE($1, 1, [Add the ]$1[ flag when building])
+	AC_DEFINE($1, m4_default([$4],[1]), [Add the ]$1[ flag when building])
 	tcl_flags="$tcl_flags $1"
     fi
 ])
@@ -2316,6 +2320,8 @@ AC_DEFUN([SC_TCL_EARLY_FLAGS],[
     tcl_flags=""
     SC_TCL_EARLY_FLAG(_ISOC99_SOURCE,[#include <stdlib.h>],
 	[char *p = (char *)strtoll; char *q = (char *)strtoull;])
+    SC_TCL_EARLY_FLAG(_FILE_OFFSET_BITS,[#include <sys/stat.h>],
+	[switch (0) { case 0: case (sizeof(off_t)==sizeof(long long)): ; }],64)
     SC_TCL_EARLY_FLAG(_LARGEFILE64_SOURCE,[#include <sys/stat.h>],
 	[struct stat64 buf; int i = stat64("/", &buf);])
     if test "x${tcl_flags}" = "x" ; then
@@ -2338,8 +2344,8 @@ AC_DEFUN([SC_TCL_EARLY_FLAGS],[
 #	Might define the following vars:
 #		TCL_WIDE_INT_IS_LONG
 #		HAVE_STRUCT_DIRENT64, HAVE_DIR64
-#		HAVE_STRUCT_STAT64
 #		HAVE_TYPE_OFF64_T
+#		_TIME_BITS
 #
 #--------------------------------------------------------------------
 
@@ -2359,6 +2365,23 @@ AC_DEFUN([SC_TCL_64BIT_FLAGS], [
     else
 	AC_MSG_RESULT([no])
 	# Now check for auxiliary declarations
+	AC_CACHE_CHECK([for 64-bit time_t], tcl_cv_time_t_64,[
+	    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>]],
+		[[switch (0) {case 0: case (sizeof(time_t)==sizeof(long long)): ;}]])],
+		[tcl_cv_time_t_64=yes],[tcl_cv_time_t_64=no])])
+	if test "x${tcl_cv_time_t_64}" = "xno" ; then
+	    # Note that _TIME_BITS=64 requires _FILE_OFFSET_BITS=64
+	    # which SC_TCL_EARLY_FLAGS has defined if necessary.
+	    AC_CACHE_CHECK([if _TIME_BITS=64 enables 64-bit time_t], tcl_cv__time_bits,[
+		AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#define _TIME_BITS 64
+#include <sys/types.h>]],
+		    [[switch (0) {case 0: case (sizeof(time_t)==sizeof(long long)): ;}]])],
+		    [tcl_cv__time_bits=yes],[tcl_cv__time_bits=no])])
+	    if test "x${tcl_cv__time_bits}" = "xyes" ; then
+		AC_DEFINE(_TIME_BITS, 64, [_TIME_BITS=64 enables 64-bit time_t.])
+	    fi
+	fi
+
 	AC_CACHE_CHECK([for struct dirent64], tcl_cv_struct_dirent64,[
 	    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
 #include <dirent.h>]], [[struct dirent64 p;]])],
@@ -2376,14 +2399,6 @@ AC_DEFUN([SC_TCL_64BIT_FLAGS], [
 	    AC_DEFINE(HAVE_DIR64, 1, [Is 'DIR64' in <sys/types.h>?])
 	fi
 
-	AC_CACHE_CHECK([for struct stat64], tcl_cv_struct_stat64,[
-	    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/stat.h>]], [[struct stat64 p;
-]])],
-		[tcl_cv_struct_stat64=yes], [tcl_cv_struct_stat64=no])])
-	if test "x${tcl_cv_struct_stat64}" = "xyes" ; then
-	    AC_DEFINE(HAVE_STRUCT_STAT64, 1, [Is 'struct stat64' in <sys/stat.h>?])
-	fi
-
 	AC_CHECK_FUNCS(open64 lseek64)
 	AC_MSG_CHECKING([for off64_t])
 	AC_CACHE_VAL(tcl_cv_type_off64_t,[
diff --git a/unix/tcl.pc.in b/unix/tcl.pc.in
index 5f90c41..9c6da82 100644
--- a/unix/tcl.pc.in
+++ b/unix/tcl.pc.in
@@ -10,7 +10,7 @@ Name: Tool Command Language
 Description: Tcl is a powerful, easy-to-learn dynamic programming language, suitable for a wide range of uses.
 URL: https://www.tcl-lang.org/
 Version: @TCL_VERSION@@TCL_PATCH_LEVEL@
-Requires.private: zlib >= 1.2.3, libtommath >= 1.2.0
+Requires.private: @TCL_PC_REQUIRES_PRIVATE@ zlib >= 1.2.3
 Libs: -L${libdir} @TCL_LIB_FLAG@ @TCL_STUB_LIB_FLAG@
 Libs.private: @TCL_LIBS@
-Cflags: -I${includedir}
+Cflags: -I${includedir} @TCL_PC_CFLAGS@
diff --git a/unix/tclConfig.h.in b/unix/tclConfig.h.in
index fe2c6d9..8500afb 100644
--- a/unix/tclConfig.h.in
+++ b/unix/tclConfig.h.in
@@ -181,6 +181,15 @@
 /* Define to 1 if you have the `OSSpinLockLock' function. */
 #undef HAVE_OSSPINLOCKLOCK
 
+/* Define to 1 if you have the `posix_spawnattr_setflags' function. */
+#undef HAVE_POSIX_SPAWNATTR_SETFLAGS
+
+/* Define to 1 if you have the `posix_spawnp' function. */
+#undef HAVE_POSIX_SPAWNP
+
+/* Define to 1 if you have the `posix_spawn_file_actions_adddup2' function. */
+#undef HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2
+
 /* Should we use pselect()? */
 #undef HAVE_PSELECT
 
@@ -229,9 +238,6 @@
 /* Define to 1 if the system has the type `struct sockaddr_storage'. */
 #undef HAVE_STRUCT_SOCKADDR_STORAGE
 
-/* Is 'struct stat64' in <sys/stat.h>? */
-#undef HAVE_STRUCT_STAT64
-
 /* Define to 1 if `st_blksize' is a member of `struct stat'. */
 #undef HAVE_STRUCT_STAT_ST_BLKSIZE
 
@@ -295,6 +301,9 @@
 /* Define to 1 if you have the <unistd.h> header file. */
 #undef HAVE_UNISTD_H
 
+/* Define to 1 if you have the `vfork' function. */
+#undef HAVE_VFORK
+
 /* Define to 1 if you have the `waitpid' function. */
 #undef HAVE_WAITPID
 
@@ -450,9 +459,6 @@
 /* Should we use FIONBIO? */
 #undef USE_FIONBIO
 
-/* Should we use vfork() instead of fork()? */
-#undef USE_VFORK
-
 /* Define WORDS_BIGENDIAN to 1 if your processor stores words with the most
    significant byte first (like Motorola and SPARC, unlike Intel). */
 #if defined AC_APPLE_UNIVERSAL_BUILD
@@ -471,6 +477,9 @@
 /* Are Darwin SUSv3 extensions available? */
 #undef _DARWIN_C_SOURCE
 
+/* Add the _FILE_OFFSET_BITS flag when building */
+#undef _FILE_OFFSET_BITS
+
 /* Add the _ISOC99_SOURCE flag when building */
 #undef _ISOC99_SOURCE
 
@@ -489,6 +498,9 @@
 /* Do we want the thread-safe OS API? */
 #undef _THREAD_SAFE
 
+/* _TIME_BITS=64 enables 64-bit time_t. */
+#undef _TIME_BITS
+
 /* Do we want to use the XOPEN network library? */
 #undef _XOPEN_SOURCE
 
diff --git a/unix/tclUnixFCmd.c b/unix/tclUnixFCmd.c
index b260cf4..dce71c4 100644
--- a/unix/tclUnixFCmd.c
+++ b/unix/tclUnixFCmd.c
@@ -266,10 +266,7 @@ MODULE_SCOPE long tclMacOSXDarwinRelease;
 #endif /* NO_REALPATH */
 
 #ifdef HAVE_FTS
-#if defined(HAVE_STRUCT_STAT64) && !defined(__APPLE__)
-/* fts doesn't do stat64 */
-#   define noFtsStat	1
-#elif defined(__APPLE__) && defined(__LP64__) && \
+#if defined(__APPLE__) && defined(__LP64__) && \
 	defined(MAC_OS_X_VERSION_MIN_REQUIRED) && \
 	MAC_OS_X_VERSION_MIN_REQUIRED < 1050
 /*
diff --git a/unix/tclUnixPipe.c b/unix/tclUnixPipe.c
index c1fae5d..4e8a758 100644
--- a/unix/tclUnixPipe.c
+++ b/unix/tclUnixPipe.c
@@ -13,7 +13,18 @@
 
 #include "tclInt.h"
 
-#ifdef USE_VFORK
+#ifdef HAVE_POSIX_SPAWNP
+#   if defined(HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2) \
+	    && defined(HAVE_POSIX_SPAWNATTR_SETFLAGS) \
+	    && !defined(HAVE_VFORK)
+#	include <unistd.h>
+#	include <spawn.h>
+#   else
+#	undef HAVE_POSIX_SPAWNP
+#   endif
+#endif
+
+#ifdef HAVE_VFORK
 #define fork vfork
 #endif
 
@@ -412,6 +423,10 @@ TclpCreateProcess(
     char **newArgv;
     int pid;
     size_t i;
+#if defined(HAVE_POSIX_SPAWNP)
+    int childErrno;
+    static int use_spawn = -1;
+#endif
 
     errPipeIn = NULL;
     errPipeOut = NULL;
@@ -440,7 +455,7 @@ TclpCreateProcess(
 	newArgv[i] = Tcl_UtfToExternalDString(NULL, argv[i], TCL_INDEX_NONE, &dsArray[i]);
     }
 
-#ifdef USE_VFORK
+#if defined(HAVE_VFORK) || defined(HAVE_POSIX_SPAWNP)
     /*
      * After vfork(), do not call code in the child that changes global state,
      * because it is using the parent's memory space at that point and writes
@@ -453,14 +468,80 @@ TclpCreateProcess(
 	Tcl_GetStdChannel(TCL_STDIN);
     }
     if (!outputFile) {
-        Tcl_GetStdChannel(TCL_STDOUT);
+	Tcl_GetStdChannel(TCL_STDOUT);
     }
     if (!errorFile) {
-        Tcl_GetStdChannel(TCL_STDERR);
+	Tcl_GetStdChannel(TCL_STDERR);
     }
 #endif
 
+#ifdef HAVE_POSIX_SPAWNP
+#ifdef _CS_GNU_LIBC_VERSION
+    if (use_spawn < 0) {
+	char conf[32], *p;
+	int major = 0, minor = 0;
+
+	use_spawn = 0;
+	memset(conf, 0, sizeof(conf));
+	confstr(_CS_GNU_LIBC_VERSION, conf, sizeof(conf));
+	p = strchr(conf, ' ');	/* skip "glibc" */
+	if (p != NULL) {
+	    ++p;
+	    if (sscanf(p, "%d.%d", &major, &minor) > 1) {
+		if ((major > 2) || ((major == 2) && (minor >= 24))) {
+		    use_spawn = 1;
+		}
+	    }
+	}
+    }
+#endif
+    status = -1;
+    if (use_spawn) {
+	posix_spawn_file_actions_t actions;
+	posix_spawnattr_t attr;
+	sigset_t sigs;
+
+	posix_spawn_file_actions_init(&actions);
+	posix_spawnattr_init(&attr);
+	sigfillset(&sigs);
+	sigdelset(&sigs, SIGKILL);
+	sigdelset(&sigs, SIGSTOP);
+
+	posix_spawnattr_setflags(&attr,
+				 POSIX_SPAWN_SETSIGDEF
+#ifdef POSIX_SPAWN_USEVFORK
+				 | POSIX_SPAWN_USEVFORK
+#endif
+				 );
+	posix_spawnattr_setsigdefault(&attr, &sigs);
+
+	posix_spawn_file_actions_adddup2(&actions, GetFd(inputFile), 0);
+	posix_spawn_file_actions_adddup2(&actions, GetFd(outputFile), 1);
+	posix_spawn_file_actions_adddup2(&actions, GetFd(errorFile), 2);
+
+	status = posix_spawnp(&pid, newArgv[0], &actions, &attr,
+			      newArgv, environ);
+	childErrno = errno;
+	posix_spawn_file_actions_destroy(&actions);
+	posix_spawnattr_destroy(&attr);
+
+	/*
+	 * Fork semantics:
+	 *  - pid == 0: child process
+	 *  - pid == -1: error
+	 *  - pid > 0: parent process
+	 *
+	 * Mimic fork semantics to minimize changes below,
+	 * but retry with fork() as last ressort.
+	 */
+    }
+    if (status != 0) {
+	pid = fork();
+	childErrno = errno;
+    }
+#else
     pid = fork();
+#endif
     if (pid == 0) {
 	size_t len;
 	int joinThisError = errorFile && (errorFile == outputFile);
@@ -510,6 +591,9 @@ TclpCreateProcess(
     TclStackFree(interp, dsArray);
 
     if (pid == -1) {
+#ifdef HAVE_POSIX_SPAWNP
+	errno = childErrno;
+#endif
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 		"couldn't fork child process: %s", Tcl_PosixError(interp)));
 	goto error;
diff --git a/unix/tclUnixPort.h b/unix/tclUnixPort.h
index 33c8971..cdc67d2 100644
--- a/unix/tclUnixPort.h
+++ b/unix/tclUnixPort.h
@@ -115,10 +115,6 @@ extern "C" {
 #ifdef __cplusplus
 }
 #endif
-#elif defined(HAVE_STRUCT_STAT64) && !defined(__APPLE__)
-#   define TclOSfstat(fd, buf) fstat64(fd, (struct stat64 *)buf)
-#   define TclOSstat(name, buf) stat64(name, (struct stat64 *)buf)
-#   define TclOSlstat(name,buf) lstat64(name, (struct stat64 *)buf)
 #else
 #   define TclOSfstat(fd, buf) fstat(fd, (struct stat *)buf)
 #   define TclOSstat(name, buf) stat(name, (struct stat *)buf)
@@ -609,23 +605,13 @@ extern char **		environ;
 	    defined(HAVE_WEAK_IMPORT) && MAC_OS_X_VERSION_MIN_REQUIRED < 1050
 #	warning "Weak import of 64-bit CoreFoundation is not supported, will not run on Mac OS X < 10.5."
 #   endif
-
-/*
- *---------------------------------------------------------------------------
- * At present, using vfork() instead of fork() causes execve() to fail
- * intermittently on Darwin x86_64. rdar://4685553
- *---------------------------------------------------------------------------
- */
-
-#   if defined(__x86_64__) && !defined(FIXED_RDAR_4685553)
-#	undef USE_VFORK
-#   endif /* __x86_64__ */
-/* Workaround problems with vfork() when building with llvm-gcc-4.2 */
-#   if defined (__llvm__) && \
-	    (__GNUC__ > 4 || (__GNUC__ == 4 && (__GNUC_MINOR__ > 2 || \
-	    (__GNUC_MINOR__ == 2 && __GNUC_PATCHLEVEL__ > 0))))
-#	undef USE_VFORK
-#   endif /* __llvm__ */
+    /*
+     * For now, test exec-17.1 fails (I/O setup after closing stdout) with
+     * posix_spawnp(), but the classic implementation (based on fork()+execvp())
+     * works well under macOS.
+     */
+#   undef HAVE_POSIX_SPAWNP
+#   undef HAVE_VFORK
 #endif /* __APPLE__ */
 
 /*