The license for sci-libs/gmsh appears to be incorrect. Currently, it's listed as:
License: GPL-3 free-noncomm
However, the license for the current version, 4.4.1, is just GPL-2 with additional rights:
Gmsh is provided under the terms of the GNU General Public License
(GPL), Version 2 or later, with the following exception:
The copyright holders of Gmsh give you permission to combine Gmsh
with code included in the standard release of TetGen (from Hang
Si), Netgen (from Joachim Sch"oberl), METIS (from George Karypis
at the University of Minnesota), OpenCASCADE (from Open CASCADE
S.A.S) and ParaView (from Kitware, Inc.) under their respective
licenses. You may copy and distribute such a system following the
terms of the GNU GPL for Gmsh and the licenses of the other code
concerned, provided that you include the source code of that other
code when and as the GNU GPL requires distribution of source code.
Note that people who make modified versions of Gmsh are not
obligated to grant this special exception for their modified
versions; it is their choice whether to do so. The GNU General
Public License gives permission to release a modified version
without this exception; this exception also makes it possible to
release a modified version which carries forward this exception.
End of exception.
GNU GENERAL PUBLIC LICENSE
Version 2, June 1991
This is the same as the current license listed on their website:
Basically, it appears to be GPL-2 with an extra rider to give additional rights. Namely, I don't believe it to be free-noncomm, which is triggering a modification to be added to package.license.
GPL-2+ appears to be the main license, but there are files licensed differently:
// Copyright (c) 1997-2005 University of Maryland and Sunil Arya and
// David Mount. All Rights Reserved.
// This software and related documentation is part of the
// Approximate Nearest Neighbor Library (ANN).
// Permission to use, copy, and distribute this software and its
// documentation is hereby granted free of charge, provided that
// (1) it is not a component of a commercial product, and
// (2) this notice appears in all copies of the software and
// related documentation.
// The University of Maryland (U.M.) and the authors make no representations
// about the suitability or fitness of this software for any purpose. It is
// provided "as is" without express or implied warranty.
By clause (1) this would be "free-noncomm".
I also see these licenses:
GPL-3+ HPND BSD-2 LGPL-2+ LGPL-2.1+ MPL-2.0 HPND MIT BSD Apache-2.0
Some of them are for files in contrib/, and I haven't checked in detail what is being installed.
Ok, good catch. I think that's for a plugin, but the license for the combined product makes the situation somewhat more complicated. I don't know the protocol for dealing with the combination of the licenses in portage, so I'll defer to whatever works for you.