Twenty-five of the ninety-seven errno messages differed from FreeBSD releng/11.4 lib/libc/gen/errlst.c (for example errno 0, 30, 47, 62, 70 and 84).
(cherry picked from commit ce14c9ad7dc639335ff72b60122bae2bd0fee302)
guest_errors sets errno to 13 and checks at the end that the strerror_r
calls left it alone, but a std::thread is created and joined in between.
Guest errno is the host's errno. Since glibc 2.42, pthread_create first
tries madvise(MADV_GUARD_INSTALL) for the new thread's stack guard.
Kernels before 6.13, including WSL2's 6.6, reject it with EINVAL, and
glibc falls back to mprotect with errno left at EINVAL. POSIX leaves
errno unspecified after a successful call, so the test aborts on Ubuntu
26.04 (glibc 2.43) under WSL2 without anything being wrong.
Check errno right after the strerror calls, and set it to 13 again after
the join, so every errno check covers only strerror and strerror_r.
Adrià
fma-rc
Hussein Kadhim
LuisBiceps
SamG-Coder