opengl: add egl-context.[ch] helpers

Add helper functions to manage opengl contexts using egl.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

ui/Makefile.objs

@@ -31,6 +31,7 @@ ifeq ($(CONFIG_OPENGL),y)
 common-obj-y += shader.o
 common-obj-y += console-gl.o
 common-obj-y += egl-helpers.o
+common-obj-y += egl-context.o
 common-obj-$(CONFIG_GTK) += gtk-egl.o
 endif