With b01524ff ("meson: don't build libGLES*.so with GLVND") we dropped the incorrect pkg-config files for GLES*.
Since then, the glvnd issue of its missing files has become painfully apparent, since it break the build for everyone using glvnd.
NVIDIA has had a fix for a few years now, but has yet to accept it:
(in their defense, it currently needs a rebase, but they could do that themselves, especially since someone already provided an up-to-date patch in the comments)
Since the breakage is already there, let's clean up everything on our side while we wait for NVIDIA to accept the fix.