Fix warning on MacOSX: "/Library/Developer/CommandLineTools/usr/bin/ranlib: file: libtcl8.6.a(tclAlloc.o) has no symbols". Backported from 8.7

5 files changed, 34 insertions, 5 deletions

diff --git a/generic/tclAlloc.c b/generic/tclAlloc.c
index 5eaa2eb..c9d5113 100644
--- a/generic/tclAlloc.c
+++ b/generic/tclAlloc.c
@@ -8,7 +8,7 @@
  *
  * Copyright (c) 1983 Regents of the University of California.
  * Copyright (c) 1996-1997 Sun Microsystems, Inc.
- * Copyright (c) 1998-1999 by Scriptics Corporation.
+ * Copyright (c) 1998-1999 Scriptics Corporation.
  *
  * Portions contributed by Chris Kingsley, Jack Jansen and Ray Johnson.
  *
@@ -275,7 +275,7 @@ TclpAlloc(
     if (numBytes >= MAXMALLOC - OVERHEAD) {
 	if (numBytes <= UINT_MAX - OVERHEAD -sizeof(struct block)) {
 	    bigBlockPtr = (struct block *) TclpSysAlloc(
-		    (sizeof(struct block) + OVERHEAD + numBytes), 0);
+		    sizeof(struct block) + OVERHEAD + numBytes, 0);
 	}
 	if (bigBlockPtr == NULL) {
 	    Tcl_MutexUnlock(allocMutexPtr);
@@ -748,6 +748,8 @@ TclpRealloc(
 }
 
 #endif /* !USE_TCLALLOC */
+#else
+TCL_MAC_EMPTY_FILE(generic_tclAlloc_c)
 #endif /* !TCL_THREADS */
 
 /*
diff --git a/generic/tclInt.h b/generic/tclInt.h
index 103827f..6550ab3 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -4503,6 +4503,27 @@ typedef struct NRE_callback {
 #endif
 
 /*
+ * Special hack for macOS, where the static linker (technically the 'ar'
+ * command) hates empty object files, and accepts no flags to make it shut up.
+ *
+ * These symbols are otherwise completely useless.
+ *
+ * They can't be written to or written through. They can't be seen by any
+ * other code. They use a separate attribute (supported by all macOS
+ * compilers, which are derivatives of clang or gcc) to stop the compilation
+ * from moaning. They will be excluded during the final linking stage.
+ *
+ * Other platforms get nothing at all. That's good.
+ */
+
+#ifdef MAC_OSX_TCL
+#define TCL_MAC_EMPTY_FILE(name) \
+    static __attribute__((used)) const void *const TclUnusedFile_ ## name = NULL;
+#else
+#define TCL_MAC_EMPTY_FILE(name)
+#endif /* MAC_OSX_TCL */
+
+/*
  * Other externals.
  */
 
diff --git a/generic/tclThreadJoin.c b/generic/tclThreadJoin.c
index d6d89a1..5c4d969 100644
--- a/generic/tclThreadJoin.c
+++ b/generic/tclThreadJoin.c
@@ -6,7 +6,7 @@
  *	provide the functionality of joining threads.  This code is currently
  *	not necessary on Unix.
  *
- * Copyright (c) 2000 by Scriptics Corporation
+ * Copyright (c) 2000 Scriptics Corporation
  *
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
@@ -230,7 +230,7 @@ TclRememberJoinableThread(
 {
     JoinableThread *threadPtr;
 
-    threadPtr = ckalloc(sizeof(JoinableThread));
+    threadPtr = (JoinableThread *)ckalloc(sizeof(JoinableThread));
     threadPtr->id = id;
     threadPtr->done = 0;
     threadPtr->waitedUpon = 0;
@@ -305,6 +305,8 @@ TclSignalExitThread(
 
     Tcl_MutexUnlock(&threadPtr->threadMutex);
 }
+#else
+TCL_MAC_EMPTY_FILE(generic_tclThreadJoin_c)
 #endif /* _WIN32 */
 
 /*
diff --git a/unix/tclUnixEvent.c b/unix/tclUnixEvent.c
index 40aac6f..7161d18 100644
--- a/unix/tclUnixEvent.c
+++ b/unix/tclUnixEvent.c
@@ -3,7 +3,7 @@
  *
  *	This file implements Unix specific event related routines.
  *
- * Copyright (c) 1997 by Sun Microsystems, Inc.
+ * Copyright (c) 1997 Sun Microsystems, Inc.
  *
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
@@ -85,6 +85,8 @@ Tcl_Sleep(
     }
 }
 
+#else
+TCL_MAC_EMPTY_FILE(unix_tclUnixEvent_c)
 #endif /* HAVE_COREFOUNDATION */
 /*
  * Local Variables:
diff --git a/unix/tclUnixNotfy.c b/unix/tclUnixNotfy.c
index 4655327..0bee2f1 100644
--- a/unix/tclUnixNotfy.c
+++ b/unix/tclUnixNotfy.c
@@ -1483,6 +1483,8 @@ AtForkChild(void)
 
 #endif /* TCL_THREADS */
 
+#else
+TCL_MAC_EMPTY_FILE(unix_tclUnixNotfy_c)
 #endif /* !HAVE_COREFOUNDATION */
 
 /*