chore: change licence to MIT-0

We've decided to simplify the Subplot licensing situation by changing
the licence to MIT-0 from the GPL.

See https://gitlab.com/subplot/subplot/-/issues/229 for agreements
from everyone involved.

Sponsored-by: author

6 files changed, 52 insertions, 32 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 4b3414f..6f90c62 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,7 +6,7 @@ authors = [
   "Daniel Silverstone <dsilvers@digital-scurf.org>",
 ]
 edition = "2018"
-license = "GPL-3.0-or-later"
+license = "MIT-0"
 description = '''
 tools for specifying, documenting,
 and implementing automated acceptance tests for systems and software'''
diff --git a/README.md b/README.md
index 6134fb5..ac8699e 100644
--- a/README.md
+++ b/README.md
@@ -59,17 +59,31 @@ $ dpkg-buildpackage -us -uc
 
 # Legalese
 
-Copyright 2019-2021  Lars Wirzenius, Daniel Silverstone
+The Subplot software is released using the MIT licence. The copy of
+the licence text is from <https://mit-license.org/> originally.
 
-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.
+## The MIT License (MIT)
 
-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.
+Copyright 2019-2021  Lars Wirzenius, Daniel Silverstone
 
-You should have received a copy of the GNU General Public License
-along with this program. If not, see <http://www.gnu.org/licenses/>.
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+“Software”), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+Fork this project to create your own MIT license that you can always
+link to.
diff --git a/debian/copyright b/debian/copyright
index a8eef8c..fe3a242 100644
--- a/debian/copyright
+++ b/debian/copyright
@@ -4,20 +4,26 @@ Upstream-Contact: Lars Wirzenius <liw@liw.fi>
 Source: http://git.liw.fi/subplot
 
 Files: *
-Copyright: 2019, Lars Wirzenius
-License: GPL-3+
- 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/>.
- .
- On a Debian system, you can find a copy of GPL version 3 at
- /usr/share/common-licenses/GPL-3 .
+Copyright: 2019-2021, Lars Wirzenius and Daniel Silverstone
+License: MIT
+ Permission is hereby granted, free of charge, to any person obtaining
+ a copy of this software and associated documentation files (the
+ “Software”), to deal in the Software without restriction, including
+ without limitation the rights to use, copy, modify, merge, publish,
+ distribute, sublicense, and/or sell copies of the Software, and to
+ permit persons to whom the Software is furnished to do so, subject to
+ the following conditions:
+
+ The above copyright notice and this permission notice shall be
+ included in all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND,
+ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+ Fork this project to create your own MIT license that you can always
+ link to.
diff --git a/subplot-build/Cargo.toml b/subplot-build/Cargo.toml
index c4fe932..ef1ca54 100644
--- a/subplot-build/Cargo.toml
+++ b/subplot-build/Cargo.toml
@@ -6,7 +6,7 @@ authors = [
   "Daniel Silverstone <dsilvers@digital-scurf.org>",
 ]
 edition = "2018"
-license = "GPL-3.0-or-later"
+license = "MIT-0"
 description = '''A library for using Subplot code generation from another project's
 `build.rs` module.'''
 homepage = "https://subplot.liw.fi/"
diff --git a/subplotlib-derive/Cargo.toml b/subplotlib-derive/Cargo.toml
index 16a1a30..ce23b65 100644
--- a/subplotlib-derive/Cargo.toml
+++ b/subplotlib-derive/Cargo.toml
@@ -6,7 +6,7 @@ authors = [
   "Daniel Silverstone <dsilvers@digital-scurf.org>",
 ]
 edition = "2018"
-license = "GPL-3.0-or-later"
+license = "MIT-0"
 description = '''
 macros for constructing subplotlib based test suites, typically
 generated by `subplot codegen`.'''
diff --git a/subplotlib/Cargo.toml b/subplotlib/Cargo.toml
index 95844b5..94004a7 100644
--- a/subplotlib/Cargo.toml
+++ b/subplotlib/Cargo.toml
@@ -6,7 +6,7 @@ authors = [
   "Daniel Silverstone <dsilvers@digital-scurf.org>",
 ]
 edition = "2018"
-license = "GPL-3.0-or-later"
+license = "MIT-0"
 description = '''
 Utility functions and types for `subplot codegen` generated Rust based
 test suites.  Relies on `subplotlib-derive` for associated macros.'''