Distribute xcb_keysym.h.

1.1.0-pre1 tarballs do not build because that file is missing. distcheck seems fine now.
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
(cherry picked from commit 1e035179)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/video_output/Modules.am

@@ -52,7 +52,7 @@ libxcb_glx_plugin_la_LIBADD = $(AM_LIBADD) \
 	$(XLIB_XCB_LIBS) $(GL_LIBS)
 libxcb_glx_plugin_la_DEPENDENCIES =
 
-libxcb_window_plugin_la_SOURCES = xcb/window.c xcb/keys.c xcb/keysym.h
+libxcb_window_plugin_la_SOURCES = xcb/window.c xcb/keys.c xcb/keysym.h xcb/xcb_keysym.h
 libxcb_window_plugin_la_CFLAGS = $(AM_CFLAGS) \
 	$(XPROTO_CFLAGS) \
 	$(XCB_CFLAGS) \