xfree
#define xfree(a) { if ((a) != NULL) { free((void *)(a)); (a) = NULL; } }
xfree(char *cp)
xfree(void *ptr)
xfree(sysdem_ops_t *ops, void *p, size_t len)
void xfree(MINT *c) { _mp_xfree(c); }
#undef xfree
#define xfree(p) free(p)