[glib] Bump gtk-doc dep to 1.20

[Matthias Clasen <matthiasc src gnome org>]

commit c81834c0895766f104bc6fb1579704066df90597
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Feb 17 16:57:13 2014 -0500

    Bump gtk-doc dep to 1.20

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index c38cd35..c4c865e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2592,7 +2592,7 @@ dnl **************************
 # gtkdocize greps for ^GTK_DOC_CHECK and parses it, so you need to have
 # it on it's own line.
 m4_ifdef([GTK_DOC_CHECK], [
-GTK_DOC_CHECK([1.15], [--flavour no-tmpl])
+GTK_DOC_CHECK([1.20], [--flavour no-tmpl])
 ],[
 AM_CONDITIONAL([ENABLE_GTK_DOC],[false])
 ])