Nico Rieck:  this patch series fixes visibility issues on Windows as explained in <http://lists.cs.uiuc.edu/pipermail/cfe-dev/2013-August/031214.html>.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@188192 91177308-0d34-0410-b5e6-96231b3b80d8