[mutter] Make it possible to build without GLX support

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit f1393605695f32f889ce76bfc568c26831efb580
Author: Jonas Ådahl <jadahl gmail com>
Date:   Tue Nov 6 16:18:56 2018 +0100

    Make it possible to build without GLX support

 configure.ac                         | 2 ++
 src/backends/meta-backend.c          | 6 ++++++
 src/backends/x11/meta-renderer-x11.c | 4 ++++
 3 files changed, 12 insertions(+)
---
diff --git a/configure.ac b/configure.ac
index 7c9694708..fdfaf614b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -290,6 +290,8 @@ AS_IF([test "$have_native_backend" = "yes"], [
 ])
 AM_CONDITIONAL([HAVE_NATIVE_BACKEND],[test "$have_native_backend" = "yes"])
 
+AC_DEFINE([HAVE_EGL],[1], [Defined if EGL support is enabled])
+
 MUTTER_WAYLAND_EGLSTREAM_MODULES="wayland-eglstream-protocols"
 
 AC_ARG_ENABLE(egl-device,
diff --git a/src/backends/meta-backend.c b/src/backends/meta-backend.c
index e86738d90..375e9d298 100644
--- a/src/backends/meta-backend.c
+++ b/src/backends/meta-backend.c
@@ -91,7 +91,9 @@ struct _MetaBackendPrivate
   MetaCursorRenderer *cursor_renderer;
   MetaInputSettings *input_settings;
   MetaRenderer *renderer;
+#ifdef HAVE_EGL
   MetaEgl *egl;
+#endif
   MetaSettings *settings;
 #ifdef HAVE_REMOTE_DESKTOP
   MetaRemoteAccessController *remote_access_controller;
@@ -774,7 +776,9 @@ meta_backend_initable_init (GInitable     *initable,
 
   priv->settings = meta_settings_new (backend);
 
+#ifdef HAVE_EGL
   priv->egl = g_object_new (META_TYPE_EGL, NULL);
+#endif
 
   priv->orientation_manager = g_object_new (META_TYPE_ORIENTATION_MANAGER, NULL);
 
@@ -885,6 +889,7 @@ meta_backend_get_renderer (MetaBackend *backend)
   return priv->renderer;
 }
 
+#ifdef HAVE_EGL
 /**
  * meta_backend_get_egl: (skip)
  */
@@ -895,6 +900,7 @@ meta_backend_get_egl (MetaBackend *backend)
 
   return priv->egl;
 }
+#endif /* HAVE_EGL */
 
 /**
  * meta_backend_get_settings: (skip)
diff --git a/src/backends/x11/meta-renderer-x11.c b/src/backends/x11/meta-renderer-x11.c
index 526861fa9..e070d63b2 100644
--- a/src/backends/x11/meta-renderer-x11.c
+++ b/src/backends/x11/meta-renderer-x11.c
@@ -60,7 +60,11 @@ get_x11_cogl_winsys_vtable (CoglRenderer *renderer)
 #endif
     case COGL_DRIVER_GL:
     case COGL_DRIVER_GL3:
+#ifdef COGL_HAS_GLX_SUPPORT
       return _cogl_winsys_glx_get_vtable ();
+#else
+      break;
+#endif
     case COGL_DRIVER_ANY:
     case COGL_DRIVER_NOP:
       break;