Adding this to GMLive's create event should work:
for (var i = 100001; script_exists(i); i++) { var s = script_get_name(i); if (gml_func_sig.h_exists(s)) continue; gml_func_add(":::" + s + "(...):", i); }
this will also add a lot of usually inaccessible functions (like struct methods) but I'll see about figuring out the right way to index extension scripts later. Only extension scripts that are still in 2.2.5 style (an extension instead of a big script) are affected.