[Bug c++/53673] Add magic weak symbol to indicate C++ standard setting (C++03, C++11 etc) to help debug ABI problems

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53673

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-06-14 
17:21:45 UTC ---
There's no point differentiating the gnu variants, they don't have any ABI
impact.

This could (and probably should) be done in the library because the output of
G++ is ABI compatible, it's only standard library components that are not.