void *xmalloc_and_zero PARAMS ((size_t n));
void *xcalloc PARAMS ((size_t n, size_t s));
void *xrealloc PARAMS ((void *p, size_t n));
void *xmalloc_and_zero PARAMS ((size_t n));
void *xcalloc PARAMS ((size_t n, size_t s));
void *xrealloc PARAMS ((void *p, size_t n));