- move gl, egl, glesv1_cm and glesv2 pkgconfig files to doc
directory, so these can be picked up by Mesa build; no longer
require Mesa devel subpackages ...

- reverting inclusion of GL, EGL, GLES, GLES2, GLES3 headers;
no longer let libglvnd-devel package provide and obsolete
corresponding Mesa gl, egl, gles* devel subpackages; headers
just aren't compatible; instead require them ...
- supersedes patches:
* n_0001-eglplatform-fix-mesa-specific-defines.patch
* u_add-gl3ext.h

- let libglvnd-devel also provide/obsolete Mesa-libGLESv3-devel

- let libglvnd-devel provide/obsolete some of previous Mesa devel
packages:
* Mesa-libGL-devel
* Mesa-libEGL-devel
* Mesa-libGLESv1_CM-devel
* Mesa-libGLESv2-devel
* Mesa-KHR-devel
- u_add-gl3ext.h
* adds missing include/GLES/gl3ext.h

- Update to version 1.2.0:
* Changes:
+ Libglvnd now includes and installs the header files for OpenGL, GLES, EGL,
and GLX.
+ Added pkg-config files for each library.
+ The X11 libraries are now an optional dependency if you're not building
GLX.
- n_0001-GL-Bump-GL-version-to-9-2.patch
* with a version of 1.2 the XServer build fails; set the version accordingly to
allow XServer builds again.
- n_0001-eglplatform-fix-mesa-specific-defines.patch
* the XServer fails to build; add the mesa specific defines to eglplatform, to
let it build again.