[clutter-gst/clutter-gst-3.0] configure.ac: fix wrong variable usage

[Lionel Landwerlin <llandwerlin src gnome org>]

commit beecd7eacc3cf01ea1f1b40dae75d67fe8f48d50
Author: Lionel Landwerlin <lionel g landwerlin intel com>
Date:   Tue Nov 24 17:33:04 2015 +0000

    configure.ac: fix wrong variable usage
    
    https://bugzilla.gnome.org/show_bug.cgi?id=758604

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 6e76a38..e7085f2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -225,7 +225,7 @@ AS_IF([test "$enable_udev" != "no"],
                             AC_DEFINE([HAVE_GUDEV], [1],
                                       ["Defined if gudev is available"])
                           ],[
-                            AS_IF([test "$with_udev" = "yes"],
+                            AS_IF([test "$enable_udev" = "yes"],
                                   [AC_MSG_ERROR([Could not find libgudev])],
                                   [have_gudev=no])
                           ])