To get some sense on how is GCC 5 standing, we (myself and Jakub Jelinek)
have performed a test mass rebuild of rawhide (January 15th package list)
using gcc-5.0.0-0.5.fc22 on x86_64, and for those packages that failed also
rebuilt the same package with gcc-4.9.2-5.fc22.x86_64 to quickly remove from
the list packages that fail for non-GCC related reasons.
There were 16230 packages overall. 15303 packages built fine, 691 packages
failed to build with both gcc-5.0.0-0.5.fc22 and gcc-4.9.2-5.fc22 (ignored for
this analysis, unlikely to be GCC 5 related).