[Bug c++/7313] variable declared but not defined with "C" linkage placed in enclosing namespace at link time

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=7313

--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-02-02 01:41:07 UTC ---
or if it is ill-formed, it's "no diagnostic required":
http://open-std.org/JTC1/SC22/WG21/docs/cwg_defects.html#564

I'm not sure whether the definitions find the same entities (and inherit their
language linkage) as the extern "C" declarations.