a few changes for weston, the wayland reference compositor (#790542):
    
    - enable gbm and shared-glapi in configure command (the latter is required by
      the former) and add subpackages libgbm and libgbm-devel
    - add --with-egl-platforms=x11,wayland,drm to configure command and add
      subpackages libwayland-egl and libwayland-egl-devel