**Is your feature request related to a problem? Please describe.** Not a problem, just some compiler warnings I got in the latest macOS with the latest Xcode. **Describe the solution you'd like** Comment and possibly act on these: filesystem.hpp:3561:44: warning: zero as null pointer constant [-Wzero-as-null-pointer-constant] if (::getcwd(buffer.get(), pathlen) == NULL) { ^~~~ nullptr filesystem.hpp:2559:12: note: call 'std::move' explicitly to avoid copying on older compilers return fn; ^~ std::move(fn) filesystem.hpp:2559:12: warning: prior to the resolution of a defect report against ISO C++11, local variable 'fn' would have been copied despite being returned by name, due to its not matching the function return type ('ghc::filesystem::path' vs 'ghc::filesystem::path::impl_string_type' (aka 'basic_string<char>')) [-Wreturn-std-move-in-c++11] return fn; ^~