Clarify licenses

- add license headers to everything
- convert a few files from public domain or LGPL2.1+ to GPL2+
- some archaeology to clarify which files are from which library

20 files changed, 53 insertions, 16 deletions

diff --git a/src/extension/dbus/CMakeLists.txt b/src/extension/dbus/CMakeLists.txt
index ad9e1fd7d..f189180d6 100644
--- a/src/extension/dbus/CMakeLists.txt
+++ b/src/extension/dbus/CMakeLists.txt
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
 if(WITH_DBUS)
 include_directories(${CMAKE_BINARY_DIR}/src/extension/dbus)
 set(dbus_SRC "")
diff --git a/src/extension/dbus/application-interface.cpp b/src/extension/dbus/application-interface.cpp
index afaf9aedf..1b4be697d 100644
--- a/src/extension/dbus/application-interface.cpp
+++ b/src/extension/dbus/application-interface.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * This is where the implementation of the DBus based application API lives.
  * All the methods in here are designed to be called remotly via DBus.
@@ -12,9 +13,9 @@
  *
  * Copyright (C) 2009 Soren Berg
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
- 
+
 #include "application-interface.h"
 #include <string.h>
 #include "dbus-init.h"
diff --git a/src/extension/dbus/application-interface.h b/src/extension/dbus/application-interface.h
index 74c37cdd3..9e9758561 100644
--- a/src/extension/dbus/application-interface.h
+++ b/src/extension/dbus/application-interface.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * This is where the implementation of the DBus based application API lives.
  * All the methods in here are designed to be called remotly via DBus.
@@ -12,7 +13,7 @@
  *
  * Copyright (C) 2009 Soren Berg
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef INKSCAPE_EXTENSION_APPLICATION_INTERFACE_H_
diff --git a/src/extension/dbus/application-interface.xml b/src/extension/dbus/application-interface.xml
index 1553971cc..38d763074 100644
--- a/src/extension/dbus/application-interface.xml
+++ b/src/extension/dbus/application-interface.xml
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 <?xml version="1.0" encoding="UTF-8" ?>
 <!--
  * This is the master description of the DBus application interface.
@@ -15,7 +16,7 @@
  *
  * Copyright (C) 2009 Soren Berg
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 -->
 <node name="/org/inkscape/application"
   xmlns:doc="http://www.freedesktop.org/dbus/1.0/doc.dtd"
diff --git a/src/extension/dbus/builddocs.sh b/src/extension/dbus/builddocs.sh
index 2c16daf41..dbe3d6ec9 100644
--- a/src/extension/dbus/builddocs.sh
+++ b/src/extension/dbus/builddocs.sh
@@ -1,3 +1,5 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-or-later
 xsltproc doc/spec-to-docbook.xsl application-interface.xml > doc/org.inkscape.application.ref.xml &&
 xsltproc doc/spec-to-docbook.xsl document-interface.xml > doc/org.inkscape.document.ref.xml &&
 xsltproc doc/spec-to-docbook.xsl proposed-interface.xml > doc/org.inkscape.proposed.ref.xml &&
diff --git a/src/extension/dbus/dbus-init.cpp b/src/extension/dbus/dbus-init.cpp
index 43830762c..29db295d7 100644
--- a/src/extension/dbus/dbus-init.cpp
+++ b/src/extension/dbus/dbus-init.cpp
@@ -1,5 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
- * This is where Inkscape connects to the DBus when it starts and 
+ * This is where Inkscape connects to the DBus when it starts and
  * registers the main interface.
  *
  * Also where new interfaces are registered when a new document is created.
@@ -10,9 +11,9 @@
  *
  * Copyright (C) 2009 Soren Berg
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
- 
+
 #include <dbus/dbus-glib.h>
 // this is reguired so that giomm headers won't barf
 #undef DBUS_MESSAGE_TYPE_INVALID
diff --git a/src/extension/dbus/dbus-init.h b/src/extension/dbus/dbus-init.h
index 7862ad3c3..c67a97dad 100644
--- a/src/extension/dbus/dbus-init.h
+++ b/src/extension/dbus/dbus-init.h
@@ -1,10 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Authors:
  *   Soren Berg <glimmer07@gmail.com>
  *
  * Copyright (C) 2009 Authors
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef INKSCAPE_EXTENSION_DBUS_INIT_H__
diff --git a/src/extension/dbus/doc/config.xsl b/src/extension/dbus/doc/config.xsl
index 26949c4ef..09cf8de5d 100644
--- a/src/extension/dbus/doc/config.xsl
+++ b/src/extension/dbus/doc/config.xsl
@@ -1,4 +1,5 @@
 <?xml version='1.0'?>
+<!-- SPDX-License-Identifier: GPL-2.0-or-later -->
 <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                 xmlns:fo="http://www.w3.org/1999/XSL/Format"
                 version="1.0">
diff --git a/src/extension/dbus/doc/dbus-introspect-docs.dtd b/src/extension/dbus/doc/dbus-introspect-docs.dtd
index 47816713e..3355d4d85 100644
--- a/src/extension/dbus/doc/dbus-introspect-docs.dtd
+++ b/src/extension/dbus/doc/dbus-introspect-docs.dtd
@@ -1,4 +1,5 @@
 <!-- DTD for D-Bus Introspection Documentation -->
+<!-- SPDX-License-Identifier: GPL-2.0-or-later -->
 
 <!ELEMENT doc (summary?,description?,errors?,permission?,since?,deprecated,seealso?)>
 
diff --git a/src/extension/dbus/doc/docbook.css b/src/extension/dbus/doc/docbook.css
index aed08dce1..0a1b7eefa 100644
--- a/src/extension/dbus/doc/docbook.css
+++ b/src/extension/dbus/doc/docbook.css
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 body
 {
   font-family: sans-serif;
diff --git a/src/extension/dbus/doc/spec-to-docbook.xsl b/src/extension/dbus/doc/spec-to-docbook.xsl
index a4e792df0..5282167e7 100644
--- a/src/extension/dbus/doc/spec-to-docbook.xsl
+++ b/src/extension/dbus/doc/spec-to-docbook.xsl
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 <?xml version='1.0'?>
 <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
   xmlns:doc="http://www.freedesktop.org/dbus/1.0/doc.dtd"
@@ -5,7 +6,7 @@
 <!--
      Convert D-Bus Glib xml into DocBook refentries
      Copyright (C) 2007 William Jon McCann
-     License: GPL
+     Released under GNU GPL v2+, read the file 'COPYING' for more information.
 -->
 <xsl:output method="xml" indent="yes" encoding="UTF-8"/>
 
diff --git a/src/extension/dbus/document-interface.cpp b/src/extension/dbus/document-interface.cpp
index 7a1f3939d..a02aa5089 100644
--- a/src/extension/dbus/document-interface.cpp
+++ b/src/extension/dbus/document-interface.cpp
@@ -1,6 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * This is where the implementation of the DBus based document API lives.
- * All the methods in here (except in the helper section) are 
+ * All the methods in here (except in the helper section) are
  * designed to be called remotely via DBus. application-interface.cpp
  * has the methods used to connect to the bus and get a document instance.
  *
@@ -12,7 +13,7 @@
  *
  * Copyright (C) 2009 Soren Berg
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #include <glib.h>
diff --git a/src/extension/dbus/document-interface.h b/src/extension/dbus/document-interface.h
index 0150dae7e..f2229a9aa 100644
--- a/src/extension/dbus/document-interface.h
+++ b/src/extension/dbus/document-interface.h
@@ -1,6 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * This is where the implementation of the DBus based document API lives.
- * All the methods in here (except in the helper section) are 
+ * All the methods in here (except in the helper section) are
  * designed to be called remotly via DBus. application-interface.cpp
  * has the methods used to connect to the bus and get a document instance.
  *
@@ -12,9 +13,9 @@
  *
  * Copyright (C) 2009 Soren Berg
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
- 
+
 #ifndef INKSCAPE_EXTENSION_DOCUMENT_INTERFACE_H_
 #define INKSCAPE_EXTENSION_DOCUMENT_INTERFACE_H_
 
diff --git a/src/extension/dbus/document-interface.xml b/src/extension/dbus/document-interface.xml
index 26fa7b117..64ff4223c 100644
--- a/src/extension/dbus/document-interface.xml
+++ b/src/extension/dbus/document-interface.xml
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 <?xml version="1.0" encoding="UTF-8" ?>
 <!--
  * This is the master description of the DBus document interface.
@@ -14,7 +15,7 @@
  *
  * Copyright (C) 2009 Soren Berg
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 -->
  
  
diff --git a/src/extension/dbus/org.inkscape.service.in b/src/extension/dbus/org.inkscape.service.in
index 484c8e516..9fffa025e 100644
--- a/src/extension/dbus/org.inkscape.service.in
+++ b/src/extension/dbus/org.inkscape.service.in
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
 [D-BUS Service]
 Name=org.inkscape
 Exec=bindir/bin/inkscape
diff --git a/src/extension/dbus/proposed-interface.xml b/src/extension/dbus/proposed-interface.xml
index 2a45c1d52..0fe995cac 100644
--- a/src/extension/dbus/proposed-interface.xml
+++ b/src/extension/dbus/proposed-interface.xml
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 <?xml version="1.0" encoding="UTF-8" ?>
 <!--
  * These are some of the proposed functions for the document interface.
@@ -12,7 +13,7 @@
  *
  * Copyright (C) 2009 Soren Berg
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 -->
 <node name="/org/inkscape/proposed"
   xmlns:doc="http://www.freedesktop.org/dbus/1.0/doc.dtd"
diff --git a/src/extension/dbus/pytester.py b/src/extension/dbus/pytester.py
index d4c41fb47..fdd7e9ab6 100644
--- a/src/extension/dbus/pytester.py
+++ b/src/extension/dbus/pytester.py
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
 #####################################################################
 # Python test script for Inkscape DBus API.
 #
diff --git a/src/extension/dbus/wrapper/inkdbus.pc.in b/src/extension/dbus/wrapper/inkdbus.pc.in
index 2bdfb75eb..512e3b34e 100644
--- a/src/extension/dbus/wrapper/inkdbus.pc.in
+++ b/src/extension/dbus/wrapper/inkdbus.pc.in
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
 prefix=@prefix@
 exec_prefix=@exec_prefix@
 libdir=@libdir@
diff --git a/src/extension/dbus/wrapper/inkscape-dbus-wrapper.c b/src/extension/dbus/wrapper/inkscape-dbus-wrapper.c
index c7e453593..cc9399cda 100644
--- a/src/extension/dbus/wrapper/inkscape-dbus-wrapper.c
+++ b/src/extension/dbus/wrapper/inkscape-dbus-wrapper.c
@@ -1,3 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * TODO: insert short description here
+ *//*
+ * Authors: see git history
+ *
+ * Copyright (C) 2013 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #include "inkscape-dbus-wrapper.h"
 #include <string.h>
 #include <stdio.h>
diff --git a/src/extension/dbus/wrapper/inkscape-dbus-wrapper.h b/src/extension/dbus/wrapper/inkscape-dbus-wrapper.h
index 20830bd65..e2abd305e 100644
--- a/src/extension/dbus/wrapper/inkscape-dbus-wrapper.h
+++ b/src/extension/dbus/wrapper/inkscape-dbus-wrapper.h
@@ -1,3 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * TODO: insert short description here
+ *//*
+ * Authors: see git history
+ *
+ * Copyright (C) 2013 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #ifndef INKSCAPE_EXTENSION_DOCUMENT_INTERFACE_H_
 #define INKSCAPE_EXTENSION_DOCUMENT_INTERFACE_H_