Tests fail: fatal error: 'ghc/filesystem.hpp' file not found

Version: 0.13.0 FreeBSD 13

Did you fix this? If so, how?

I was able to fix it by installing the https://github.com/gulrak/filesystem.git library and using cmake -D CMAKE_INSTALL_PREFIX=../xtl_install to compile and then make to install it.