Renaming -0.38.1.ebuild and commenting out 'epatch ${FILESDIR}/string.patch' seems to work. Reproducible: Always Steps to Reproduce: 1. 2. 3.
There really should be a gtkmm dependancy too - in 0.39pre4, there was also a problem with configure not liking gtkmm-2.4.* , though it builds fine one the detect is modified.
There's an ebuild for 0.39 in portage, please check it out and file any new bug you might find. Thanks, Marc