This is a header-only single-file std::filesystem compatible helper
library, based on the C++17 and C++20 specs, but implemented for C++11,
C++14, C++17 or C++20 (tightly following the C++17 standard with very
few documented exceptions).

It is currently tested on macOS 10.12/10.14/10.15/11.6, Windows 10,
Ubuntu 18.04, Ubuntu 20.04, CentOS 7, CentOS 8, FreeBSD 12,
Alpine ARM/ARM64 Linux and Solaris 10 but should work on other
systems too, as long as you have at least a C++11 compatible compiler.
It should work with Android NDK, Emscripten and I even had reports of
it being used on iOS (within sandboxing constraints) and with v1.5.6
there is experimental support for QNX. The support of Android NDK,
Emscripten and QNX is not backed up by automated testing but PRs and
bug reports are welcome for those too. It is of course in its own
namespace ghc::filesystem to not interfere with a regular
std::filesystem should you use it in a mixed C++17 environment
(which is possible).