+
+#ifndef HAVE_MEMRCHR
+/* memrchr is a GNU extension. It is like the memchr function, except
+ that it searches backwards from the end of the n bytes pointed to
+ by s instead of forwards from the front. */
+
+void *
+memrchr (const void *s, int c, size_t n)
+{
+ const char *b = s;
+ const char *e = b + n;
+ while (e > b)
+ if (*--e == c)
+ return (void *) e;
+ return NULL;
+}
+#endif