free hook

extern void* (*__MALLOC_HOOK_VOLATILE __malloc_hook)(size_t __size, const void*);
extern void* (*__MALLOC_HOOK_VOLATILE __realloc_hook)(void* __ptr, size_t __size, const void*);
extern void* (*__MALLOC_HOOK_VOLATILE __memalign_hook)(size_t __alignment, size_t __size, const void*);
extern void (*__MALLOC_HOOK_VOLATILE __free_hook)(void* __ptr, const void*);

removed in glibc 2.34