mcheck: Use memset/memcpy instead of MALLOC_ZERO/MALLOC_COPY for mcheck.

These fast helpers sometimes breach mem-chunk boundaries.
Thus they trigger mcheck alarm. Standard ones are accurate though.

Signed-off-by: Eugene Uriev <eugeneuriev@gmail.com>

common/dlmalloc.c

@@ -34,6 +34,10 @@ DECLARE_GLOBAL_DATA_PTR;
 
 #ifdef MCHECK_HEAP_PROTECTION
  #define STATIC_IF_MCHECK static
+ #undef MALLOC_COPY
+ #undef MALLOC_ZERO
+static inline void MALLOC_ZERO(void *p, size_t sz) { memset(p, 0, sz); }
+static inline void MALLOC_COPY(void *dest, const void *src, size_t sz) { memcpy(dest, src, sz); }
 #else
  #define STATIC_IF_MCHECK
  #define mALLOc_impl mALLOc