cuetools.net/flac/src/share

This directory contains several convenience libraries used by the rest of the
tools and plugins.  Two of them (getopt and utf8) are shamelessly copied from
vorbistools, one for manipulating UTF-8 strings (GPL) and one for implementing
getopt (LGPL).  libFLAC does not link to either; the only FLAC tools that do
are GPL'ed.