fix compile error when EGL_BUFFER_AGE_EXT is missing
fix compile error when EGL_BUFFER_AGE_EXT is missing

Signed-off-by: Adrian Negreanu <6275e895b07c55965e568461471033e41dc8e923@intel.com>

jonnylamb/weston,eyolfson/weston,udoprog/weston,Tarnyko/weston-xdg_surface_present,sir-murray/weston,sir-murray/weston,giucam/weston,eyolfson/weston,Fantu/compositor-spice,xorgy/weston,giucam/weston,Gnurou/weston,Fantu/compositor-spice,Gnurou/weston,Fantu/compositor-spice,mchalupa/weston,kwm81/weston,Tarnyko/weston-xdg_surface_present,kwm81/weston,krezovic/weston,krezovic/weston,udoprog/weston,jonnylamb/weston,mchalupa/weston,xorgy/weston