[libsoup] Avoid the need of gtk-doc if anyway we do not want it

[Ignacio Casal Quinteiro <icq src gnome org>]

commit d28b6f3531520c6613264cedc4010733345ca3cd
Author: Ignacio Casal Quinteiro <icq gnome org>
Date:   Mon Aug 31 17:32:12 2015 +0200

    Avoid the need of gtk-doc if anyway we do not want it

 configure.ac |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index eac02db..582ed49 100644
--- a/configure.ac
+++ b/configure.ac
@@ -155,7 +155,11 @@ AC_SUBST(HAVE_GNOME)
 dnl ***************
 dnl *** gtk-doc ***
 dnl ***************
-GTK_DOC_CHECK([1.10])
+# 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([1.20], [--flavour no-tmpl])
+],[])
 
 dnl *****************************
 dnl *** gobject-introspection ***