Very many testcases, some GLib tools (resource compiler, etc) and
GApplication were calling g_type_init().
Remove those uses, as they are no longer required.
https://bugzilla.gnome.org/show_bug.cgi?id=686161
Transforming a GValue holding flags from a GFlagsValue set that includes the 0
value (no flag bits set) into a string would loop until exhausting all the
available memory.
https://bugzilla.gnome.org/show_bug.cgi?id=670557