Bug report
Makefile.pre.in and configure.ac are using the realpath command for some targets. For example WASI HOSTRUNNER uses realpath --relative-to to get the working directory relative to the srcdir root directory. macOS seems to lack realpath, breaking WASI tests, see #95828 (comment)
For WASI HOSTRUNNER we need to replace realpath somehow. Or find a different approach to fix testing with OOT builds. The HOSTRUNNER for WASI is complicated because we have to make srcdir available to WASI runtime environment. --mapdir /::$(srcdir) maps the srcdir to root / inside the runtime environment. wasmtime sets cwd to /, so our logic to find pybuilddir.txt does not work. That's why the HOSTRUNNER sets --env PYTHONPATH=/$(shell realpath --relative-to $(abs_srcdir) $(abs_builddir))/$(shell cat pybuilddir.txt):/Lib, which resolves to --env PYTHONPATH=/builddir/wasi/build/lib.wasi-wasm32-3.12:/Lib on my system. The prefix depends on the OOT builddir. The suffix is read from pybuilddir.txt, which is generated at the end of the build process.