sys-fs/encfs-1.5 does not compile with USE='-nls'. It seems that support for _not_ using nls in encfs is rather broken: A missing definition of ngettext(a,b,c) without this flag could easily be added, but some boost libraries seem to require libintl.h anyway which breaks with the fake gettext() macro. I did not delve into the boost internals whether this inclusion could somehow be omitted, but it looked not that easy, so I am afraid that the nls dependency must be made unconditional.
Thanks for reporting this issue. Assigning report to maintainer, who will probably agree with you about making the dependency unconditional.
Maintainer appears to be away or busy.
+ 27 Jun 2010; Samuli Suominen <ssuominen@gentoo.org> encfs-1.6.ebuild: + Remove USE="nls" wrt #277239 by Martin Väth.