License update

To be more compliant regarding GCC / GNU licences

COPYING.RUNTIME

@@ -0,0 +1,73 @@
+GCC RUNTIME LIBRARY EXCEPTION
+
+Version 3.1, 31 March 2009
+
+Copyright (C) 2009 Free Software Foundation, Inc. <http://fsf.org/>
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+This GCC Runtime Library Exception ("Exception") is an additional
+permission under section 7 of the GNU General Public License, version
+3 ("GPLv3"). It applies to a given file (the "Runtime Library") that
+bears a notice placed by the copyright holder of the file stating that
+the file is governed by GPLv3 along with this Exception.
+
+When you use GCC to compile a program, GCC may combine portions of
+certain GCC header files and runtime libraries with the compiled
+program. The purpose of this Exception is to allow compilation of
+non-GPL (including proprietary) programs to use, in this way, the
+header files and runtime libraries covered by this Exception.
+
+0. Definitions.
+
+A file is an "Independent Module" if it either requires the Runtime
+Library for execution after a Compilation Process, or makes use of an
+interface provided by the Runtime Library, but is not otherwise based
+on the Runtime Library.
+
+"GCC" means a version of the GNU Compiler Collection, with or without
+modifications, governed by version 3 (or a specified later version) of
+the GNU General Public License (GPL) with the option of using any
+subsequent versions published by the FSF.
+
+"GPL-compatible Software" is software whose conditions of propagation,
+modification and use would permit combination with GCC in accord with
+the license of GCC.
+
+"Target Code" refers to output from any compiler for a real or virtual
+target processor architecture, in executable form or suitable for
+input to an assembler, loader, linker and/or execution
+phase. Notwithstanding that, Target Code does not include data in any
+format that is used as a compiler intermediate representation, or used
+for producing a compiler intermediate representation.
+
+The "Compilation Process" transforms code entirely represented in
+non-intermediate languages designed for human-written code, and/or in
+Java Virtual Machine byte code, into Target Code. Thus, for example,
+use of source code generators and preprocessors need not be considered
+part of the Compilation Process, since the Compilation Process can be
+understood as starting with the output of the generators or
+preprocessors.
+
+A Compilation Process is "Eligible" if it is done using GCC, alone or
+with other GPL-compatible software, or if it is done without using any
+work based on GCC. For example, using non-GPL-compatible Software to
+optimize any GCC intermediate representations would not qualify as an
+Eligible Compilation Process.
+
+1. Grant of Additional Permission.
+
+You have permission to propagate a work of Target Code formed by
+combining the Runtime Library with Independent Modules, even if such
+propagation would otherwise violate the terms of GPLv3, provided that
+all Target Code was generated by Eligible Compilation Processes. You
+may then convey such a combination under terms of your choice,
+consistent with the licensing of the Independent Modules.
+
+2. No Weakening of GCC Copyleft.
+
+The availability of this Exception does not imply any general
+presumption that third-party software is unaffected by the copyleft
+requirements of the license of GCC.
+

license.txt

@@ -1,4 +1,4 @@
-MIT License - Copyright (c) 2016 Stephane Dallongeville
+MIT License - Copyright (c) 2019 Stephane Dallongeville
 
 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,

readme.txt

@@ -1,10 +1,12 @@
 SGDK 1.34 (december 2017)
-Copyright Stephane Dallongeville
+Copyright 2019 Stephane Dallongeville
 https://stephane-d.github.io/SGDK/
 
 SGDK is an open and free development kit for the Sega Megadrive.
-It contains a development library (sources included) to make software on Sega Megadrive / Genesis system which is accompanied by a GCC compiler toolchains (binaries provided for Windows OS only) and some tools used to build the ROM.
-SGDK and affiliated tools are distribued under the MIT license (see license.txt file).
+It contains a development library (sources included) to make software for the Sega Megadrive / Genesis system and it uses the GCC compiler plus some custom tools to build the ROM (binaries are provided for Windows OS for convenience) .
+
+SGDK library and custom tools are distributed under the MIT license (see license.txt file).
+GCC compiler and libgcc are under GNU licences (GPL3) and any software build from it (as the SGDK library) is under the GCC runtime library exception license (see COPYING.RUNTIME file)
 
 You can find the library doxygen documentation in the 'doc' directory: doc/html/files.html
 
@@ -27,4 +29,4 @@ https://github.com/v4ld3r5/sgdk_vscode_template
 If you enjoy SGDK you can support it using the donation link:
 https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=2SCWVXYDEEBUU
 
-Thanks =) I wish you a happy coding time !
+Thanks =) I wish you a happy coding time !