meson: re-add incorrect pkg-config files with GLVND for backward compatibility

This is a bit counter-intuitive, but the issue is that GLVND is broken
in versions <= 1.1.1, so we need to keep wrongly providing these files
to cover up their mistake, otherwise the rest of the world ends up
broken.

Suggested-by: Dylan Baker <dylan@pnwbakers.com>
Cc: mesa-stable@lists.freedesktop.org
Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
(cherry picked from commit 93df862b)