[clutter] Fix Makefile to properly include clutter-backend-eglnative.h in the disted tarball

[Emmanuele Bassi <ebassi src gnome org>]

commit 047f60b13829bc8fee66c9107e90f1aacf40cf93
Author: Tristan Van Berkom <tristanvb openismus com>
Date:   Sat Feb 4 22:43:51 2012 +0900

    Fix Makefile to properly include clutter-backend-eglnative.h in the disted tarball
    
    https://bugzilla.gnome.org/show_bug.cgi?id=669360

 clutter/Makefile.am |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/clutter/Makefile.am b/clutter/Makefile.am
index c77d247..eb790bf 100644
--- a/clutter/Makefile.am
+++ b/clutter/Makefile.am
@@ -614,6 +614,7 @@ endif
 if SUPPORT_EGL
 backend_source_h += $(egl_source_h)
 backend_source_c += $(egl_source_c)
+backend_source_h_priv += $(egl_source_h_priv)
 
 clutteregl_includedir = $(clutter_includedir)/egl
 clutteregl_include_HEADERS = $(egl_source_h)