void *nmalloc(size_t nbytes)
{
        void *ptr = ( nbytes == 0 ) ? NULL : calloc( nbytes, sizeof( void * ) ) ;
        if(!ptr)
                fatal("out of memory");
        return ptr;
}

void *nrealloc(void *p, size_t nb)
{
        void *newp = ( nb == 0 ) ? NULL : realloc(p, nb);
        if(!newp)
                fatal("out of memory");
        return newp;
}

void nfree(void *ptr)
{
#ifdef DEBUG
        static void *last_ptr = NULL;
#endif
        if(ptr == NULL)
                return;
#ifdef DEBUG
        if(last_ptr == ptr)
                fatal("internal error: attempting to free same pointer twice");
        else
#endif
        if(ptr)
                free(ptr);
}