egl: Sync with Khronos

    commit de3a5e867d906a04a5c37ee0d89e7f01d3598eb9
    Author: Ken Russell <kbrussel@alum.mit.edu>
    Date:   Sat Oct 12 05:44:43 2019 -0700

        Reserve enums 0x34A0..0x34AF for ANGLE project. (#93)

Closes: https://gitlab.freedesktop.org/glvnd/libglvnd/issues/193