lib: Don't export gettext init function

abicheck.sh threw an error because of the wrongly prefixed was used
in commit: f37f850abe714f19cd3d7e2d5e3bd93483d1ec8a
lib: Make gdk_pixbuf_fill() fail if pixbuf doesn't have storage

This fixes a crash when using Python's "new" keyword instead of the
constructors exported by GdkPixbuf.

See https://bugzilla.gnome.org/show_bug.cgi?id=658702
gif: Fix loading GIF if first write is smaller than 13 bytes

https://bugzilla.gnome.org/show_bug.cgi?id=581461
tests: Add test case for short GIF writes

Based on the test program from Andrey Tsyvarev <tsyvarev@ispras.ru>

https://bugzilla.gnome.org/show_bug.cgi?id=581461