[gtk+] Bump glib dep to 2.31.20

[Matthias Clasen <matthiasc src gnome org>]

commit 185973983ac5117ace6eeefd0dcbae3a3ec53a44
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Mar 5 08:15:54 2012 -0500

    Bump glib dep to 2.31.20
    
    Needed for --valist-marshallers

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 2056223..0e2985d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -39,7 +39,7 @@ AC_CONFIG_AUX_DIR([build-aux])
 m4_define([gtk_binary_version], [3.0.0])
 
 # required versions of other packages
-m4_define([glib_required_version], [2.31.18])
+m4_define([glib_required_version], [2.31.20])
 m4_define([pango_required_version], [1.29.0])
 m4_define([atk_required_version], [2.1.5])
 m4_define([cairo_required_version], [1.10.0])