[gtk-doc] build files: add copyright headers

[Stefan Sauer <stefkost src gnome org>]

commit dd6b96534076471689f542b7e8469ec7eff521d3
Author: Stefan Sauer <ensonic users sf net>
Date:   Wed Oct 25 19:43:59 2017 +0200

    build files: add copyright headers
    
    This files are copied into the build via gtkdocize (gtk-doc.{m4,make}) or
    manually copied (examples/Makefile.am). Clarify their license.
    
    Fixes #788991

 examples/Makefile.am |   18 ++++++++++++++++++
 gtk-doc.m4           |   18 ++++++++++++++++++
 gtk-doc.make         |   18 ++++++++++++++++++
 3 files changed, 54 insertions(+), 0 deletions(-)
---
diff --git a/examples/Makefile.am b/examples/Makefile.am
index 471527f..17c88a3 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -1,3 +1,21 @@
+# -*- mode: makefile -*-
+#
+# Makefile.am - template makefile for gtk-doc module
+# Copyright (C) 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/>.
+
 # This is a blank Makefile.am for using gtk-doc.
 # Copy this to your project's API docs directory and modify the variables to
 # suit your project. See the GTK+ Makefiles in gtk+/docs/reference for examples
diff --git a/gtk-doc.m4 b/gtk-doc.m4
index 3675543..ace6e8e 100644
--- a/gtk-doc.m4
+++ b/gtk-doc.m4
@@ -1,4 +1,22 @@
 dnl -*- mode: autoconf -*-
+dnl
+dnl gtk-doc.m4 - configure macro to check for gtk-doc
+dnl Copyright (C) 2003 James Henstridge
+dnl               2007-2017  Stefan Sauer
+dnl
+dnl This program is free software: you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation, either version 3 of the License, or
+dnl (at your option) any later version.
+dnl
+dnl This program is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+dnl GNU General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU General Public License
+dnl along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 
 # serial 2
 
diff --git a/gtk-doc.make b/gtk-doc.make
index d2a8b33..f87eaab 100644
--- a/gtk-doc.make
+++ b/gtk-doc.make
@@ -1,4 +1,22 @@
 # -*- mode: makefile -*-
+#
+# gtk-doc.make - make rules for gtk-doc
+# Copyright (C) 2003 James Henstridge
+#               2004-2007 Damon Chaplin
+#               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/>.
 
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 # Everything below here is generic #