diff -r eeca1427ce51 code/nel/include/nel/misc/mutex.h
--- a/code/nel/include/nel/misc/mutex.h	Fri May 07 10:10:55 2010 +0200
+++ b/code/nel/include/nel/misc/mutex.h	Mon May 10 21:07:45 2010 +0200
@@ -237,7 +237,11 @@
 #	endif // NL_DEBUG
 #	endif // NL_NO_ASM
 #else
-		ASM_ASWAP_FOR_GCC_XCHG
+    // GCC implements the same functionality using a builtin function
+    // http://gcc.gnu.org/onlinedocs/gcc/Atomic-Builtins.html
+    // the macro below crashed on Mac OS X 10.6 in a 64bit build
+    //ASM_ASWAP_FOR_GCC_XCHG
+    result = __sync_bool_compare_and_swap(lockPtr, 0, 1);
 #endif // NL_OS_WINDOWS
 		return result != 0;
 	}