build: update builtin gtk-doc support

From gtkdocize (gtk-doc) 1.33.0.

1 files changed, 26 insertions, 1 deletions

diff --git a/m4/gtk-doc.m4 b/m4/gtk-doc.m4
index 3675543..2d12f01 100644
--- a/m4/gtk-doc.m4
+++ b/m4/gtk-doc.m4
@@ -1,4 +1,29 @@
-dnl -*- mode: autoconf -*-
+# -*- mode: autoconf -*-
+#
+# gtk-doc.m4 - configure macro to check for gtk-doc
+# Copyright (C) 2003 James Henstridge
+#               2007-2017  Stefan Sauer
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# As a special exception, the above copyright owner gives unlimited
+# permission to copy, distribute and modify the configure scripts that
+# are the output of Autoconf when processing the Macro. You need not
+# follow the terms of the GNU General Public License when using or
+# distributing such scripts, even though portions of the text of the
+# Macro appear in them. The GNU General Public License (GPL) does govern
+# all other use of the material that constitutes the Autoconf Macro.
 
 # serial 2