message: Make stdout-*.log readable (open in shared for reading mode) and non-buffered.
diff: @@ -1308,7 +1308,9 @@ namespace vcpkg
  WriteFilePointer::WriteFilePointer(const Path& file_path, std::error_code& ec) noexcept
  {
  #if defined(_WIN32)
  - ec.assign(::_wfopen_s(&m_fs, to_stdfs_path(file_path).c_str(), L"wb"), std::generic_category());
  + m_fs = ::_wfsopen(to_stdfs_path(file_path).c_str(), L"wb", _SH_DENYWR);
  + ec.assign(m_fs == nullptr ? errno : 0, std::generic_category());
  + if (m_fs != nullptr) ::setvbuf(m_fs, NULL, _IONBF, 0);
  #else // ^^^ _WIN32 / !_WIN32 vvv
  m_fs = ::fopen(file_path.c_str(), "wb");
  if (m_fs)
  