[gegl] Fixes message if intltool isn't present

[Michael Murà <mmure src gnome org>]

commit 2545a0de0eee821a53c6dc193df5872a9f5500b6
Author: Harald Korneliussen <vintermann gmail com>
Date:   Sun May 6 11:12:37 2012 +0200

    Fixes message if intltool isn't present

 configure.ac |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index df935ad..f00eaa6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -482,7 +482,9 @@ AC_CHECK_FUNCS(bind_textdomain_codeset,,
 ]))
 LIBS=$gegl_save_LIBS
 
-IT_PROG_INTLTOOL(0.40.1)
+m4_ifdef([IT_PROG_INTLTOOL],[IT_PROG_INTLTOOL(0.40.1),],
+  AC_MSG_ERROR([*** intltool version 0.40.1 or later required]))
+
 AM_GLIB_GNU_GETTEXT
 
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