Because path can be constructed from a ton of different types, including string
and wide strings, this caused it's streaming operators to suck up all sorts
of silly types via silly conversions. For example:
using namespace std::experimental::filesystem::v1;
std::wstring w(L"wide");
std::cout << w; // converts to path.
This patch tentatively adopts the resolution to LWG2989 and fixes the issue
by making the streaming operators friends of path.
llvm-svn: 324189
be71d336bd