GLib is the low-level core library that forms the basis of GTK+ and GNOME. It provides data structure handling for C, portability wrappers, and interfaces for such runtime functionality as an event loop, threads, dynamic loading, and an object system. Copy the contents of this archive to the directory, where your AROS development directory is located. If you are cross-compiling on Unix, this will most likely be the i686-aros directory.