fatal error: 'filesystem' file not found

[ryandesign]

openal-soft 1.24.0 doesn't build on macOS 10.14 or earlier:

utils/makemhr/loaddef.cpp:33:10: fatal error: 'filesystem' file not found
#include <filesystem>
         ^~~~~~~~~~~~

Full build log: https://build.macports.org/builders/ports-10.14_x86_64-builder/builds/223612/steps/install-port/logs/stdio

It builds on macOS 12 and later.

This is a regression; 1.23.1 didn't have this problem.

std::filesystem is part of C++17 but the version of libc++ included with macOS 10.14 and earlier doesn't support it. Compiling with a newer version of clang that supports C++17 is not sufficient.

[kcat]

std::filesystem is part of C++17 but the version of libc++ included with macOS 10.14 and earlier doesn't support it. Compiling with a newer version of clang that supports C++17 is not sufficient.

You should be able to static-link libc++. There is the ALSOFT_STATIC_STDCXX cmake option to link with -static-libstdc++, which the prebuilt Windows binaries use to avoid needing libstdc++.dll. According to this stackoverflow comment, it should work with Clang when using libc++ too (for Clang 14 at least; older versions may need to use a more esoteric command like -Wl,--push-state,-Bstatic,-lc++,-lc++abi,-Wl,--pop-state or something).