05.02.2008 Thread-safe class initializers

(page moved)

I finally got around to fix a long-standing and tricky bug report: Bug 64764 - Class initialization isn't thread safe.
Thread safety problems in class initializers and _get_type() functions caused nasty problems in other components that depend on parallel type creation, in particular GStreamer (Dependency Graph for bug 64764). With both being fixed now, testing feedback about GType/GObject threading problems using GLib trunk is appreciated.