You're receiving this bug because the package in Summary has produced _FORTIFY_SOURCE related warnings indicating the presence of a sure overflow in a static buffer.
Even though this is not always an indication of a security problem it might even be. So please check this out ASAP.
By the way, _FORTIFY_SOURCE is disabled when you disable optimisation, so don't try finding out the cause using -O0.
Your friendly neighborhood tinderboxer
Created attachment 248146 [details]
+*ctwm-3.8a-r1 (22 Oct 2010)
+ 22 Oct 2010; Kacper Kowalik <firstname.lastname@example.org> -ctwm-3.8a.ebuild,
+ Fix buffer overflows wrt bug 338180. Thanks to Diego for the report. Fix
+ implicit function declarations, drop redundant die messages. Drop old.