package/giflib: New package

This package will replace libungif.

Needed for Kodi 15.0, TexturePacker depends on giflib >= 5.0.5
https://github.com/xbmc/xbmc/blob/master/tools/depends/native/TexturePacker/src/configure.ac#L29



Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>