LICENSE="FDL-1.3 GPL-3" units.texinfo: ... Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. ... Aside from getopt.h, every .c and .h file has: ... 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, or (at your option) any later version. ... getopt.h: ... 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, or (at your option) any later version. ... Therefore, should be: LICENSE="GPL-3+ FDL-1.3+"