GTree with a default key comparison function

[Flavio Ribeiro <fr ime usp br>]

Hello,

I've noticed that unlike GHashTable, GTree currently doesn't accept a 
default key comparison function. The overhead of calling a trivial 
pointer comparison function is probably acceptable for most 
applications, but it's a problem in some of my code.

If the developers think this is a worthy modification, I'm willing to 
submit a GLib-2.4.0 patch to support a default direct comparison as 
implemented in hash tables.

Best regards,

Flavio