Two host differences failed all 19 feupdateenv tests on macOS:
- Apple's libc++ looks up /usr/lib/libstdc++.6.dylib with a no-load
dlopen the first time a process builds a std::logic_error, and that
failed lookup leaves errno at ENOENT. The null check builds the first
one, so it saw errno change although feupdateenv never touched it. The
test now builds one std::invalid_argument on macOS before the checks.
- Rosetta 2 keeps the six MXCSR exception masks set and raises no
floating-point trap, x87 included. The mask check now expects the SSE
masks the host keeps, and the pending-trap tests are skipped (exit 77)
on a host that does not keep an unmasked MXCSR exception. A libc debt
entry for feupdateenv records it.
Emanuele