[Bug libstdc++/50348] -fvisibility=hidden doesn't hide stl implementation details.

[pluto at agmk dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50348

--- Comment #4 from Pawel Sikora <pluto at agmk dot net> 2011-09-22 11:23:14 UTC ---
(In reply to comment #3)

> I think that, unless not imposed by the standard (why??) the visibility of
> "namespace std" SHALL NOT BE forced to default

part of the std:: (exceptions typeinfo symbols) must be visible-by-default
for proper throw-catch/dynamic_cast working across shared libs boundaries.