Merge remote-tracking branch 'remotes/kraxel/tags/pull-sdl-20150505-1' into staging
sdl2: add opengl support
# gpg: Signature made Tue May 5 10:36:25 2015 BST using RSA key ID D3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg: aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg: aka "Gerd Hoffmann (private) <kraxel@gmail.com>"
* remotes/kraxel/tags/pull-sdl-20150505-1:
sdl2: Fix RGB555
sdl2: add support for display rendering using opengl.
sdl2: move SDL_* includes to sdl2.h
console-gl: add opengl rendering helper functions
opengl: add shader helper functions.
opengl: add shader build infrastructure
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>