opengl: add shader build infrastructure

opengl: add shader build infrastructure

perl script to transform shader programs into c include files with
static string constands containing the shader programs, so we can
easily embed them into qemu.  Also some Makefile logic for them.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>