We just build and deliver glxinfo and glxgears

--- a/src/meson.build	2023-03-02 09:32:40.781537018 -0800
+++ b/src/meson.build	2023-03-02 09:40:29.033966687 -0800
@@ -22,36 +22,10 @@
 
 subdir('util')
 
-if dep_glut.found()
-  subdir('demos')
-  subdir('tests')
-  subdir('trivial')
-  subdir('redbook')
-  subdir('samples')
-  subdir('perf')
-  subdir('objviewer')
-
-  subdir('glsl')
-  subdir('fp')
-  subdir('fpglsl')
-  subdir('vp')
-  subdir('vpglsl')
-  subdir('gs')
-  subdir('tools')
-endif
-
-if dep_egl.found()
-  subdir('egl')
-endif
-
 if dep_x11.found()
   subdir('xdemos')
 endif
 
-if dep_osmesa.found()
-  subdir('osdemos')
-endif
-
 if host_machine.system() == 'windows'
   subdir('wgl')
 endif