Replace X-allocation functions with their C89 counterparts

The only remaining X-functions used in server are XNF*, the rest is converted to
plain alloc/calloc/realloc/free/strdup.

X* functions are still exported from server and x* macros are still defined in
header file, so both ABI and API are not affected by this change.

Signed-off-by: Mikhail Gusarov <dottedmag@dottedmag.net>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>

Xi/getmmap.c

@@ -113,7 +113,7 @@ ProcXGetDeviceModifierMapping(ClientPtr client)
     WriteReplyToClient(client, sizeof(xGetDeviceModifierMappingReply), &rep);
     WriteToClient(client, max_keys_per_mod * 8, (char *) modkeymap);
 
-    xfree(modkeymap);
+    free(modkeymap);
 
     return Success;
 }