Index: libgcc/config/darwin-crt-tm.c
===================================================================
--- libgcc/config/darwin-crt-tm.c	(revision 195764)
+++ libgcc/config/darwin-crt-tm.c	(working copy)
@@ -103,9 +103,12 @@ void __doTMdeRegistrations (void)
     _ITM_deregisterTMCloneTable (tmct);
 }
 
+#if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && \
+            __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__  < 1060
+
 /* Provide dummy functions to satisfy linkage for versions of the Darwin 
    tool-chain that that can't handle undefined weak refs at the link stage.
-   ??? Define these dummy functions only when !HAVE_ELF_STYLE_WEAKREF. */
+   Don't define for 10.6 or later with faster weak-symbol coalescing. */
 
 extern void *__cxa_allocate_exception (size_t) WEAK;
 extern void __cxa_throw (void *, void *, void *) WEAK;
@@ -144,5 +147,5 @@ void _ZdlPvRKSt9nothrow_t (void * a UNUS
 void *_ZnaXRKSt9nothrow_t (size_t s UNUSED, c_nothrow_p b UNUSED)
   { return NULL; }
 void _ZdaPvRKSt9nothrow_t (void * a UNUSED, c_nothrow_p b UNUSED) { return; }
-
+#endif
 #endif
Index: gcc/config/i386/darwin.h
===================================================================
--- gcc/config/i386/darwin.h	(revision 195764)
+++ gcc/config/i386/darwin.h	(working copy)
@@ -131,8 +131,7 @@ extern int darwin_emit_branch_islands;
   "%{Ofast|ffast-math|funsafe-math-optimizations:crtfastmath.o%s} \
    %{mpc32:crtprec32.o%s} \
    %{mpc64:crtprec64.o%s} \
-   %{mpc80:crtprec80.o%s} \
-   %{fgnu-tm: -lcrttme.o}"
+   %{mpc80:crtprec80.o%s}" TM_DESTRUCTOR
 
 #undef SUBTARGET_EXTRA_SPECS
 #define SUBTARGET_EXTRA_SPECS                                   \
Index: gcc/config/darwin.h
===================================================================
--- gcc/config/darwin.h	(revision 195764)
+++ gcc/config/darwin.h	(working copy)
@@ -363,7 +363,8 @@ extern GTY(()) int darwin_ms_struct;
   %{shared-libgcc:%:version-compare(< 10.5 mmacosx-version-min= crt3.o%s)}"
 
 /* We want a destructor last in the list.  */
-#define ENDFILE_SPEC "%{fgnu-tm: -lcrttme.o}"
+#define TM_DESTRUCTOR "%{fgnu-tm: -lcrttme.o}"
+#define ENDFILE_SPEC TM_DESTRUCTOR
 
 #define DARWIN_EXTRA_SPECS						\
   { "darwin_crt1", DARWIN_CRT1_SPEC },					\