http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53429
--- Comment #1 from Jeffrey Yasskin <jyasskin at gcc dot gnu.org> 2012-05-21 04:03:26 UTC --- So far, this is purely a theoretical incompatibility. I haven't actually seen a compiled libstdc++.so that exposes a version-specific complex::{imag,real}.