[gtk+] build: Don't use Wayland GtkClipboard implementation if also building for X

[Rob Bradford <rbradford src gnome org>]

commit 13b2720308e277433b8c304af241fa3fd37f472a
Author: Rob Bradford <rob linux intel com>
Date:   Thu Mar 22 12:11:57 2012 +0000

    build: Don't use Wayland GtkClipboard implementation if also building for X
    
    Workaround for: https://bugzilla.gnome.org/show_bug.cgi?id=672358

 gtk/Makefile.am |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/gtk/Makefile.am b/gtk/Makefile.am
index e40232e..e939a77 100644
--- a/gtk/Makefile.am
+++ b/gtk/Makefile.am
@@ -904,6 +904,7 @@ gtk_clipboard_dnd_c_sources = 	\
 	gtkdnd-quartz.c
 else
 if USE_WAYLAND
+if !USE_X11
 # No wayland gtkdnd-wayland.c yet
 gtk_clipboard_dnd_c_sources = 	\
 	gtkclipboard-wayland.c \
@@ -911,6 +912,9 @@ gtk_clipboard_dnd_c_sources = 	\
 else
 gtk_clipboard_dnd_c_sources = gtkclipboard.c gtkdnd.c
 endif
+else
+gtk_clipboard_dnd_c_sources = gtkclipboard.c gtkdnd.c
+endif
 endif
 
 # we use our own built_sources variable rules to avoid automake's