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

28 files changed, 170 insertions, 34 deletions

diff --git a/src/svg/CMakeLists.txt b/src/svg/CMakeLists.txt
index ff4bb63ab..ceffcbb24 100644
--- a/src/svg/CMakeLists.txt
+++ b/src/svg/CMakeLists.txt
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
 
 set(svg_SRC
 	css-ostringstream.cpp
diff --git a/src/svg/css-ostringstream-test.h b/src/svg/css-ostringstream-test.h
index fe2016d43..ed8af2d77 100644
--- a/src/svg/css-ostringstream-test.h
+++ b/src/svg/css-ostringstream-test.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) 2010 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #include <cxxtest/TestSuite.h>
 #include "svg/css-ostringstream.h"
 
diff --git a/src/svg/css-ostringstream.cpp b/src/svg/css-ostringstream.cpp
index ef0413372..e476f9f1a 100644
--- a/src/svg/css-ostringstream.cpp
+++ b/src/svg/css-ostringstream.cpp
@@ -1,3 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * TODO: insert short description here
+ *//*
+ * Authors: see git history
+ *
+ * Copyright (C) 2018 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #include "svg/css-ostringstream.h"
 #include "svg/strip-trailing-zeros.h"
 #include "preferences.h"
diff --git a/src/svg/css-ostringstream.h b/src/svg/css-ostringstream.h
index 2c66dff16..b334da50f 100644
--- a/src/svg/css-ostringstream.h
+++ b/src/svg/css-ostringstream.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) 2014 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #ifndef SVG_CSS_OSTRINGSTREAM_H_INKSCAPE
 #define SVG_CSS_OSTRINGSTREAM_H_INKSCAPE
 
diff --git a/src/svg/path-string.cpp b/src/svg/path-string.cpp
index 2fa2c8f02..95771ce08 100644
--- a/src/svg/path-string.cpp
+++ b/src/svg/path-string.cpp
@@ -1,16 +1,14 @@
-/*
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
  * Inkscape::SVG::PathString - builder for SVG path strings
- *
+ *//*
+ * Authors: see git history
+ * 
  * Copyright 2008 Jasper van de Gronde <th.v.d.gronde@hccnet.nl>
  * Copyright 2013 Tavmjong Bah <tavmjong@free.fr>
- *
- * 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 2
- * of the License, or (at your option) any later version.
- *
- * See the file COPYING for details.
- *
+ * Copyright (C) 2018 Authors
+ * 
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #include "svg/path-string.h"
diff --git a/src/svg/path-string.h b/src/svg/path-string.h
index 6c7e23017..53080ba32 100644
--- a/src/svg/path-string.h
+++ b/src/svg/path-string.h
@@ -1,15 +1,15 @@
-/*
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * Inkscape::SVG::PathString - builder for SVG path strings
+ *//*
+ * Authors: see git history
+ * 
  * Copyright 2007 MenTaLguY <mental@rydia.net>
  * Copyright 2008 Jasper van de Gronde <th.v.d.gronde@hccnet.nl>
  * Copyright 2013 Tavmjong Bah <tavmjong@free.fr>
- *
- * 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 2
- * of the License, or (at your option) any later version.
- *
- * See the file COPYING for details.
- *
+ * Copyright (C) 2014 Authors
+ * 
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_SVG_PATH_STRING_H
diff --git a/src/svg/sp-svg.def b/src/svg/sp-svg.def
index 2f013f218..6336f9b11 100644
--- a/src/svg/sp-svg.def
+++ b/src/svg/sp-svg.def
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
 EXPORTS
 	gnome_canvas_bpath_def_art_finish
 	gnome_canvas_bpath_def_closepath
diff --git a/src/svg/stringstream-test.h b/src/svg/stringstream-test.h
index 305cf6b8d..868c9a029 100644
--- a/src/svg/stringstream-test.h
+++ b/src/svg/stringstream-test.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) 2014 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #include <cxxtest/TestSuite.h>
 #include "svg/stringstream.h"
 #include <2geom/point.h>
diff --git a/src/svg/stringstream.cpp b/src/svg/stringstream.cpp
index ef7587154..3a56e9f4f 100644
--- a/src/svg/stringstream.cpp
+++ b/src/svg/stringstream.cpp
@@ -1,3 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * TODO: insert short description here
+ *//*
+ * Authors: see git history
+ *
+ * Copyright (C) 2018 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #include "svg/stringstream.h"
 #include "svg/strip-trailing-zeros.h"
 #include "preferences.h"
diff --git a/src/svg/stringstream.h b/src/svg/stringstream.h
index c9cfdd601..056ca07e8 100644
--- a/src/svg/stringstream.h
+++ b/src/svg/stringstream.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) 2014 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #ifndef INKSCAPE_STRINGSTREAM_H
 #define INKSCAPE_STRINGSTREAM_H
 
diff --git a/src/svg/strip-trailing-zeros.cpp b/src/svg/strip-trailing-zeros.cpp
index 47da93249..f6ffaf8cc 100644
--- a/src/svg/strip-trailing-zeros.cpp
+++ b/src/svg/strip-trailing-zeros.cpp
@@ -1,3 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * TODO: insert short description here
+ *//*
+ * Authors: see git history
+ *
+ * Copyright (C) 2018 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 
 #include <cstring>
 #include <string>
diff --git a/src/svg/strip-trailing-zeros.h b/src/svg/strip-trailing-zeros.h
index 697be6227..1c5f537d4 100644
--- a/src/svg/strip-trailing-zeros.h
+++ b/src/svg/strip-trailing-zeros.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) 2010 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #ifndef SVG_STRIP_TRAILING_ZEROS_H_SEEN
 #define SVG_STRIP_TRAILING_ZEROS_H_SEEN
 
diff --git a/src/svg/svg-affine-test.h b/src/svg/svg-affine-test.h
index 829ef8a5a..fcb9db048 100644
--- a/src/svg/svg-affine-test.h
+++ b/src/svg/svg-affine-test.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) 2017 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #include <cxxtest/TestSuite.h>
 
 #include "svg/svg.h"
diff --git a/src/svg/svg-affine.cpp b/src/svg/svg-affine.cpp
index 43d3a5b62..adea723d0 100644
--- a/src/svg/svg-affine.cpp
+++ b/src/svg/svg-affine.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * SVG data parser
  *
@@ -8,7 +9,7 @@
  * Copyright (C) 1999-2002 Lauris Kaplinski
  * Copyright (C) 1999 Raph Levien
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #include <cstring>
diff --git a/src/svg/svg-angle.cpp b/src/svg/svg-angle.cpp
index a991a4145..e82d0de45 100644
--- a/src/svg/svg-angle.cpp
+++ b/src/svg/svg-angle.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /**
  *  \file src/svg/svg-angle.cpp
  *  \brief SVG angle type
@@ -9,7 +10,7 @@
  * Copyright (C) 1999-2002 Lauris Kaplinski
  * Copyright (C) 2000-2001 Ximian, Inc.
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #include <cstring>
diff --git a/src/svg/svg-angle.h b/src/svg/svg-angle.h
index 966491174..6ed59153a 100644
--- a/src/svg/svg-angle.h
+++ b/src/svg/svg-angle.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 #ifndef SEEN_SP_SVG_ANGLE_H
 #define SEEN_SP_SVG_ANGLE_H
 
@@ -12,7 +13,7 @@
  * Copyright (C) 1999-2002 Lauris Kaplinski
  * Copyright (C) 2000-2001 Ximian, Inc.
  *
- * 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/svg/svg-color-test.h b/src/svg/svg-color-test.h
index e077cc43d..b1723cb38 100644
--- a/src/svg/svg-color-test.h
+++ b/src/svg/svg-color-test.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) 2010 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #include <cxxtest/TestSuite.h>
 #include <cassert>
 #include <cstdlib>
diff --git a/src/svg/svg-color.cpp b/src/svg/svg-color.cpp
index b66ca7118..fd3615d0d 100644
--- a/src/svg/svg-color.cpp
+++ b/src/svg/svg-color.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /**
  * \file
  * Reading \& writing of SVG/CSS colors.
@@ -8,7 +9,7 @@
  *
  * Copyright (C) 1999-2002 Lauris Kaplinski
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifdef HAVE_CONFIG_H
diff --git a/src/svg/svg-color.h b/src/svg/svg-color.h
index ea0896872..6b1cc02a9 100644
--- a/src/svg/svg-color.h
+++ b/src/svg/svg-color.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) 2014 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #ifndef SVG_SVG_COLOR_H_SEEN
 #define SVG_SVG_COLOR_H_SEEN
 
diff --git a/src/svg/svg-icc-color.h b/src/svg/svg-icc-color.h
index a8e498594..2a1f89ef7 100644
--- a/src/svg/svg-icc-color.h
+++ b/src/svg/svg-icc-color.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) 2010 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #ifndef SVG_ICC_COLOR_H_SEEN
 #define SVG_ICC_COLOR_H_SEEN
 
diff --git a/src/svg/svg-length-test.h b/src/svg/svg-length-test.h
index 2bdd904b1..38f20463e 100644
--- a/src/svg/svg-length-test.h
+++ b/src/svg/svg-length-test.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) 2018 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #include <cxxtest/TestSuite.h>
 
 #include "svg/svg-length.h"
diff --git a/src/svg/svg-length.cpp b/src/svg/svg-length.cpp
index a004a2518..262c6e1d5 100644
--- a/src/svg/svg-length.cpp
+++ b/src/svg/svg-length.cpp
@@ -1,13 +1,14 @@
-/**
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
  * SVG data parser
- *
- * Authors:
+ *//*
+ * Authors: see git history
+ 
  *   Lauris Kaplinski <lauris@kaplinski.com>
  *   bulia byak <buliabyak@users.sf.net>
  *
- * Copyright (C) 1999-2002 Lauris Kaplinski
- *
- * This code is in public domain
+ * Copyright (C) 2018 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #include <cmath>
diff --git a/src/svg/svg-length.h b/src/svg/svg-length.h
index 4663aced4..17e04a2ad 100644
--- a/src/svg/svg-length.h
+++ b/src/svg/svg-length.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /**
  * Authors:
  *   Lauris Kaplinski <lauris@kaplinski.com>
@@ -6,7 +7,7 @@
  * Copyright (C) 1999-2002 Lauris Kaplinski
  * Copyright (C) 2000-2001 Ximian, Inc.
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_SP_SVG_LENGTH_H
diff --git a/src/svg/svg-path-geom-test.h b/src/svg/svg-path-geom-test.h
index c3972133d..acfcc287a 100644
--- a/src/svg/svg-path-geom-test.h
+++ b/src/svg/svg-path-geom-test.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) 2015 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #include <cxxtest/TestSuite.h>
 #include "2geom/coord.h"
 #include "2geom/curves.h"
diff --git a/src/svg/svg-path.cpp b/src/svg/svg-path.cpp
index 13795f2a3..6867cfd96 100644
--- a/src/svg/svg-path.cpp
+++ b/src/svg/svg-path.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * svg-path.cpp: Parse SVG path element data into bezier path.
  * Authors:
@@ -12,7 +13,7 @@
  *
  * Copyright (C) 2000-2008 authors
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #include <cstring>
diff --git a/src/svg/svg.h b/src/svg/svg.h
index 6ce9db937..b28358695 100644
--- a/src/svg/svg.h
+++ b/src/svg/svg.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 #ifndef SEEN_SP_SVG_H
 #define SEEN_SP_SVG_H
 
@@ -9,7 +10,7 @@
  *
  * Copyright (C) 1999-2002 Lauris Kaplinski
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #include <vector>
diff --git a/src/svg/test-stubs.cpp b/src/svg/test-stubs.cpp
index 9c287cfda..b511c7e88 100644
--- a/src/svg/test-stubs.cpp
+++ b/src/svg/test-stubs.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Stub out functions when building tests
  *
@@ -6,7 +7,7 @@
  *
  * Copyright (C) 2007 authors
  *
- * 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/svg/test-stubs.h b/src/svg/test-stubs.h
index 32acc0ef5..0275f61ed 100644
--- a/src/svg/test-stubs.h
+++ b/src/svg/test-stubs.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Stub out functions when building tests
  *
@@ -6,7 +7,7 @@
  *
  * Copyright (C) 2007 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 SEEN_TEST_STUBS_H