http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40056
--- Comment #11 from Fons Rademakers <Fons.Rademakers at cern dot ch> 2012-03-08 21:16:57 UTC --- Hi Andrew, the source code now (r43307) uses explicit instantiation and should work on Gentoo with all compiler versions and optimization levels. If you want older versions to work remove the conditionals at the bottom of io/io/Module.mk. Issue can be closed. Cheers, Fons.