egl_dri2 x11: Workaround device_name xcb-dri2 bug

This commit is basically a copy-over of the fix
Chia-I Wu's commited to wayland:
   http://cgit.freedesktop.org/wayland/wayland-demos/commit/?id=1b6c0ed95
   "Workaround an xcb-dri2 bug.
    xcb_dri2_connect_device_name generated by xcb-proto 1.6 is broken.
    It only works when the length of the driver name is a multiple of 4."
2 files changed