urldate: undef hideous memory defines

The public axTLS header (at least as of 1.2.7) redefines the memory
functions. We #undef those again immediately after the public header to
limit the damage. This should be fixed in axTLS.

lib/urldata.h

@@ -122,6 +122,9 @@
 
 #ifdef USE_AXTLS
 #include <axTLS/ssl.h>
+#undef malloc
+#undef calloc
+#undef realloc
 #endif /* USE_AXTLS */
 
 #ifdef HAVE_NETINET_IN_H