meson: Add dep_glvnd to egl deps when building with glvnd

Otherwise if glvnd is not installed systemwide, but only in a prefix,
it's headers wont be found. This happens because if it's headers are in
/usr/include/ then another dependence will provide the necessary -I
arguments and compilation will work.

Fixes: 035ec7a2bb
       ("meson: Add support for EGL glvnd")
Acked-by: Eric Engestrom <eric@engestrom.ch>

src/egl/meson.build

@@ -1,4 +1,4 @@
-# Copyright © 2017 Intel Corporation
+# Copyright © 2017-2019 Intel Corporation
 
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -149,6 +149,7 @@ if not with_glvnd
 else
   egl_lib_name = 'EGL_mesa'
   egl_lib_version = '0.0.0'
+  deps_for_egl += dep_glvnd
   files_egl += [g_egldispatchstubs_h, g_egldispatchstubs_c]
   files_egl += files('main/eglglvnd.c', 'main/egldispatchstubs.c')
   install_data(