Gentoo's Bugzilla –
Attachment 411194 Details for
Bug 559802dev-qt/qtcore:5 fails to emerge on ia64 (qatomic_ia64.h:1038:6: error: prototype for ‘bool QBasicAtomicOps<size>::testAndSetRelaxed(T&, T, T)’ does not match any in class ‘QBasicAtomicOps<size>'