gitlab CI: add a basic build test

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
6 jobs for CI in 2 minutes and 23 seconds (queued for 1 second)
latest
Name Stage Failure
failed
build Build
      |          ^~~~~~
compilation terminated.
make[2]: Leaving directory '/builds/alanc/xf86-video-tga/_builddir/src'
make[2]: *** [Makefile:513: BT463ramdac.lo] Error 1
make[1]: Leaving directory '/builds/alanc/xf86-video-tga/_builddir'
make[1]: *** [Makefile:444: all-recursive] Error 1
make: *** [Makefile:376: all] Error 2
Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1