I see this breakage as well (building on Linux for NetBSD-VAX),
consistently on a local filesystem. (It's now covered by an even
earlier breakage due to a small issue with GCC 14.)
Indeed, the `cd ../lib` part seems to not work, I found this in the
build log (cf.
http://toolchain.lug-owl.de/laminar/log/netbsd-vax-vax/164):
[bld rel 2025-10-09 22:28:12] + echo dependall ===> tests/lib/libpthread/weak/test
[bld rel 2025-10-09 22:28:12] dependall ===> tests/lib/libpthread/weak/test
[bld rel 2025-10-09 22:28:12] + cd /var/lib/laminar/run/netbsd-vax-vax/164/NetBSD-src/tests/lib/libpthread/weak/test
[bld rel 2025-10-09 22:28:12] + /var/lib/laminar/run/netbsd-vax-vax/164/tools-vax-vax/bin/nbmake _THISDIR_=tests/lib/libpthread/weak/test/ dependall
[bld rel 2025-10-09 22:28:12] /usr/bin/sh: 1: cd: can't cd to ../lib
[bld rel 2025-10-09 22:28:12] nbmake[9]: /var/lib/laminar/run/netbsd-vax-vax/164/NetBSD-src/tests/lib/libpthread/weak/test/Makefile:14: warning: Command "cd ../lib && /var/lib/laminar/run/netbsd-vax-vax/164/tools-vax-vax/bin/nbmake -B -V .OBJDIR" exited with status 2
[bld rel 2025-10-09 22:28:12] echo '# ' " create " test/t_pthread_weak_nothread.d
[bld rel 2025-10-09 22:28:12] + echo # create test/t_pthread_weak_nothread.d
[bld rel 2025-10-09 22:28:12] # create test/t_pthread_weak_nothread.d