[Bug libstdc++/51813] [4.7 Regression] -fvisibility=hidden causes std::codecvt members to be undefined

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51813

--- Comment #7 from Jason Merrill <jason at gcc dot gnu.org> 2012-01-13 16:52:41 UTC ---
The right answer would seem to be wrapping includes of C headers in #pragma GCC
visibility push/pop, like many of the libsupc++ headers do.  But I'm not sure
why the compiler wants to emit a .hidden directive for this symbol but not
other hidden externs; I'll look into that.