Merge branch 'np/malloc-threading' into maint

* np/malloc-threading:
  Thread-safe xmalloc and xrealloc needs a recursive mutex
  Make xmalloc and xrealloc thread-safe

git-compat-util.h

@@ -356,6 +356,8 @@ static inline void *gitmempcpy(void *dest, const void *src, size_t n)
 
 extern void release_pack_memory(size_t, int);
 
+extern void set_try_to_free_routine(void (*routine)(size_t));
+
 extern char *xstrdup(const char *str);
 extern void *xmalloc(size_t size);
 extern void *xmallocz(size_t size);