gnu: sdl: Explicitly link against libXext.

* gnu/packages/sdl.scm (sdl): Add #:configure-flags to 'arguments'.
  Move PKG-CONFIG to 'native-inputs'.

gnu: Rename (gnu packages oggvorbis) to (gnu packages xiph).

* gnu/packages/oggvorbis.scm: Rename this ...
* gnu/packages/xiph.scm: ... to this. Adjust module name accordingly.
* gnu-system.am (GNU_SYSTEM_MODULES): Update.
* gnu/packages/{gnunet.scm, libcanberra.scm, mp3.scm, pulseaudio.scm, sdl.scm,
    video.scm}: Use new module name.

gnu: mesa: Move out of xorg.scm and into gl.scm

* gnu/packages/xorg.scm (mesa): Move to...
* gnu/packages/gl.scm (mesa): ... here.  New variable.
* gnu/packages/gnome.scm, gnu/packages/gnuzilla.scm,
  gnu/packages/qemu.scm, gnu/packages/qt.scm: Adjust accordingly.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu: sdl: Propagate libx11.

* gnu/packages/sdl.scm (sdl): Propagate LIBX11.
  (sdl-gfx, sdl-ttf): Remove LIBX11 from 'inputs'.

gnu: Add SDL extension libraries.

* gnu/packages/sdl.scm (sdl-gfx, sdl-image, sdl-mixer, sdl-net, sdl-ttf): New
  variables.

Merge branch 'master' into core-updates

Conflicts:
	guix/packages.scm

gnu: Add SDL and SDL2.

* gnu/packages/sdl.scm (sdl, sdl2): New variables.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

Merge branch 'master' into core-updates

gnu: Add libmikmod.

* gnu/packages/sdl.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.

Signed-off-by: Andreas Enge <andreas@enge.fr>