[clutter] build: fix Makefile.am to build glx tfp code on x11 platforms

[Robert Bragg <rbragg src gnome org>]

commit d65161a7fd38859a0e2db3362f9822b0956c4a62
Author: Robert Bragg <robert linux intel com>
Date:   Mon Jul 4 15:16:50 2011 +0100

    build: fix Makefile.am to build glx tfp code on x11 platforms
    
    It was already the intention that the ClutterGLXTexturePixmap API should
    be built and made available on any X11 based platforms since there was
    nothing specific about the API and it is useful to have for
    compatibility. There was a mistake in the Makefile.am though which meant
    only the header was getting installed but the code wasn't being built.
    
    Signed-off-by: Emmanuele Bassi <ebassi linux intel com>

 clutter/Makefile.am |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/clutter/Makefile.am b/clutter/Makefile.am
index 946a5d5..d2a377b 100644
--- a/clutter/Makefile.am
+++ b/clutter/Makefile.am
@@ -375,7 +375,7 @@ if SUPPORT_X11
 #
 # Note: there wasn't actually anything GLX specific so we can add
 # the compatability if clutter supports x11
-glx_source_c = $(srcdir)/cogl/clutter-glx-texture-pixmap.c
+backend_source_c += $(srcdir)/cogl/clutter-glx-texture-pixmap.c
 glx_source_h = $(srcdir)/cogl/clutter-glx-texture-pixmap.h \
 	       $(srcdir)/cogl/clutter-glx.h
 clutterglx_includedir = $(clutter_includedir)/glx