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 249544 [details]
Please add emerge --info as I cannot reproduce it on my system with gcc-4.4.4-r2 and glibc-2.12.1-r1
+*ccp4-libs-6.1.3-r4 (04 Oct 2010)
+ 04 Oct 2010; Kacper Kowalik <firstname.lastname@example.org>
+ +files/6.1.3-overflows.patch, +ccp4-libs-6.1.3-r4.ebuild:
+ Fix buffer overflows wrt bug 339706. Thanks to Diego for the report.