meson: remove dep_glx

It's just an array holding two external dependencies, and we usually use
dep_* to mean "here's a dependency object that subprojects can use".

meson.build

@@ -105,7 +105,6 @@ elif not get_option('glx').disabled() and dep_x11.found()
   dep_glproto = dependency('glproto', required : get_option('glx'))
   with_glx = true
 endif
-dep_glx = [dep_xext, dep_glproto]
 
 if cc.compiles('typeof(int *);', name : 'typeof')
   add_project_arguments('-DHAVE_TYPEOF', language : ['c'])

src/GLX/meson.build

@@ -41,7 +41,8 @@ libGLX = shared_library(
   include_directories : [inc_include],
   link_args : '-Wl,-Bsymbolic',
   dependencies : [
-    dep_dl, dep_x11, dep_glx, idep_gldispatch, idep_trace,
+    dep_dl, dep_x11, dep_xext, dep_glproto,
+    idep_gldispatch, idep_trace,
     idep_glvnd_pthread, idep_utils_misc,
     idep_app_error_check, idep_winsys_dispatch,
   ],