gen-casefold-txt.pl and gen-casemap-txt.pl are licensed under GPLv2+, so
they are not touched by this commit.
A lot of *.c files in tests/ don't have a license header.
https://bugzilla.gnome.org/show_bug.cgi?id=776504
We have some testcases that assert that type modules are unloaded after
the last reference on them is dropped. Comment out those asserts now
that we turned the last unref into a no-op.
https://bugzilla.gnome.org/show_bug.cgi?id=693351
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