Add entry for GCC (#15473)

THIRD-PARTY-NOTICES.TXT

@@ -59,6 +59,88 @@ License notice for Apple
 Content: https://github.com/mono/mono/blob/435f968102d0820ca65d63e1e741e4130b4d1303/support/ios/net/route.h
 License: https://opensource.apple.com/apsl/
 
+License for GCC
+---------------
+
+License: http://gcc.gnu.org/onlinedocs/gcc-4.6.4/libstdc++/manual/manual/license.html
+Content: https://github.com/mono/mono/blob/c398e19d3515c6bbb6046ed014b2095594a15229/mono/mini
+Example: https://github.com/mono/mono/blob/c398e19d3515c6bbb6046ed014b2095594a15229/mono/mini/decompose.c#L967
+
+GCC RUNTIME LIBRARY EXCEPTION
+
+Version 3.1, 31 March 2009
+
+Copyright (C) 2009 Free Software Foundation, Inc.
+
+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.
+    
+
+Hopefully that text is self-explanatory. If it isn't, you need to speak to your lawyer, or the Free Software Foundation.
 
 License notice for Silicon Graphics and HP
 ------------------------------------------