branches/zip: sync0sync.h: Define mutex_free as mutex0_free, because symbols

defined in innodb_redefine.h must not be undefined.  After this change,
innodb_redefine.h will define mutex0_free instead of mutex_free, and
everything is fine.

include/sync0sync.h

@@ -76,6 +76,10 @@ the mutex is freed. Removes a mutex object from the mutex list. The mutex
 is checked to be in the reset state. */
 
 #undef mutex_free			/* Fix for MacOS X */
+#define mutex_free mutex0_free		/* Fix for innodb_redefine.h;
+					we must not undefine symbols
+					defined there; thus, that file
+					will use mutex0_free. */
 void
 mutex_free(
 /*=======*/