[mutter] Include libdrm and gbm when building Clutter

[Emmanuele Bassi <ebassi src gnome org>]

commit 0f78357a5fa30c953f59f4559b6401f7581ab6f4
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Apr 28 12:39:02 2016 +0100

    Include libdrm and gbm when building Clutter
    
    Clutter out of tree depends on Cogl's required dependencies via the
    pkg-config file. Since Clutter and Cogl moved in tree, it means that
    those dependencies need to be checked by Clutter itself, otherwise
    headers and libraries won't be found.

 clutter/configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/clutter/configure.ac b/clutter/configure.ac
index c57324c..3fb791a 100644
--- a/clutter/configure.ac
+++ b/clutter/configure.ac
@@ -226,7 +226,7 @@ CLUTTER_BACKENDS="$CLUTTER_BACKENDS egl"
 SUPPORT_EGL=1
 AC_DEFINE([CLUTTER_EGL_BACKEND_GENERIC], [1], [Use Generic EGL backend])
 
-BACKEND_PC_FILES="$BACKEND_PC_FILES wayland-server"
+BACKEND_PC_FILES="$BACKEND_PC_FILES wayland-egl wayland-server libdrm gbm"
 SUPPORT_WAYLAND_COMPOSITOR=1
 CLUTTER_CONFIG_DEFINES="$CLUTTER_CONFIG_DEFINES
 #define CLUTTER_HAS_WAYLAND_COMPOSITOR_SUPPORT 1"