[Bug 35631] Add giflib support

http://bugs.winehq.org/show_bug.cgi?id=35631

--- Comment #6 from Ken Thomases  ---
(In reply to Dmitry Timoshkov from comment #5)
> (In reply to Jerome Leclanche from comment #4)
> > Maybe upstreaming some of the changes (or making them a compile-time option
> > for giflib) should be considered?
>
> Feel free to do that, all the changes are in dlls/windowscodecs/ungif.c

Careful!  The changes are LGPL while the original seems to be MIT licensed.