Add builds to the CI script that use the TSD dispatch stubs, but use the
TLS variable in u_current_tls.c for the dispatch table.
That's the combination you'd get with musl or other non-glibc systems.
Change the 'tls' option to be a boolean value instead of a feature.
This still allows manually disabling TLS in builds that would otherwise
support it, but it shouldn't be affected by meson's --auto-features
option.
Add a .gitlab-ci.yml file to run libglvnd's unit tests.
The "build-distcheck" target will simply run "make distcheck". That should also
cover running the unit tests for the x86-64 TLS build.
The "build-i386", "build-i386-tsd", and "build-x86-64-tsd" targets will build
and test the x86 TLS and TSD builds and the x86-64 TSD build.
The pure C stubs aren't covered yet, but they'll be easy to add once the unit
tests are fixed for them.
ARM and PPC builds also aren't covered yet.
Kyle Brenneman