[clutter] build: Remove unused internal define

[Emmanuele Bassi <ebassi src gnome org>]

commit 0bb5993b2bc9d746935243f66d0a567790fca44d
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Sun Mar 22 15:41:28 2015 +0000

    build: Remove unused internal define
    
    We haven't use HAVE_CLUTTER_GLX internally for a while; the last user
    was Cally, which has been ported to the correct CLUTTER_WINDOWING_X11
    symbol.

 configure.ac |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 8ddd98c..6cb98d5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -322,8 +322,6 @@ AS_IF([test "x$enable_x11" = "xyes"],
                            BACKEND_PC_FILES_PRIVATE="$BACKEND_PC_FILES_PRIVATE pangoft2"
                          ],
                          [])
-
-        AC_DEFINE([HAVE_CLUTTER_GLX], [1], [Have the GLX backend])
       ])
 
 AS_IF([test "x$enable_gdk" = "xyes"],