Remove visibility attributes from out-of-class method definitions in iostreams.

No point in pretending that these methods are hidden - they are
actually exported from libc++.so. Extern template declarations make
them part of libc++ ABI.

This patch does not change libc++.so export list (at least on Linux).

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@255177 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed