zcalloc
strm->zalloc = zcalloc;
strm->zalloc = zcalloc;
strm->zalloc = zcalloc;
voidpf ZLIB_INTERNAL zcalloc(voidpf opaque, unsigned items,
void *zcalloc(void *, unsigned int, unsigned int);
void *zcalloc(void *, unsigned int, unsigned int);
voidpf zcalloc(voidpf opaque, unsigned items, unsigned size);
z->zalloc = zcalloc;
strm->zalloc = zcalloc;