- let Mesa-libEGL-devel require libX11 devel via "pkgconfig(x11)"
since EGL/eglplatform.h includes X11/Xlib.h

- Update to version 19.2.1
* fixes all over the tree: intel, amd, nine, nir, egl, gallium,
scons, meson, glsl, haiku, android, and nouveau all got fixes.

- pickup gl, egl, glesv1_cm and glesv2 pkgconfig files from
libglvnd build and add them to the appropriate devel subpackages

- reintroduce GL, EGL, GLES* devel subpackages since corresponding
header and pkgconfig files from libglvnd didn't work out ...

- Rebase n_opencl_dep_libclang.patch after update.

- Update to version 19.2.0 including changes to
* release-infastructure
* the build
* drivers: turnip, radv, android, intel and amd common code
* new features: check Phoronix
https://www.phoronix.com/scan.php?page=news_item&px=Mesa-19.2-Released
- supersedes U_llvmpipe-Don-t-use-u_ringbuffer-for-lp_scene_queue.patch
- adjusted n_drirc-disable-rgb10-for-chromium-on-amd.patch
- supersedes n_glesv1_cm-glesv2.patch

- no longer build
* Mesa-libGL-devel
* Mesa-libEGL-devel
* Mesa-libGLESv1_CM-devel
* Mesa-libGLESv2-devel
* Mesa-libGLESv3-devel
Instead of requiring these let Mesa-devel package require
libglvnd-devel >= 1.2.0, which provides the contents of these
packages now (header files for OpenGL, GLES, EGL, and GLX).
Adjusted baselibs.conf accordingly.
- modified check for llvm version in a way so it works also with
older llvm packages (by making use of "llvm-config -version"),
where there is %{_llvm_sonum} macro defined yet
- moved manual pages to Mesa-devel package

- n_opencl_dep_libclang.patch
* Link OpenCL library with libclang-cpp.so instead of the
component libraries for LLVM >= 9.