New Config.in variables was added:
* BR2_PACKAGE_RECALBOX_HAS_LIBGLES when board is capable of OpenGles <= 2
* BR2_PACKAGE_RECALBOX_HAS_LIBGLES3 if board is capable of OpenGles <= 3.x
* BR2_PACKAGE_RECALBOX_HAS_KMS if board runs KMS
* BR2_PACKAGE_RECALBOX_EGL_NO_X11 if board does not run on X11
* BR2_PACKAGE_RECALBOX_HAS_SLANG if board support Slang shaders