Rare parallel build issue (`bpf-unknown-none-ld: cannot open output file build/dlibs/bpf_dlib.o: No such file or directory`)

I've only hit this a few times with MAKEOPTS=-j32 -l32.

bpf-unknown-none-ld -o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/dlibs/bpf_dlib.o -r /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--agg_lqbin.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--agg_qbin.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--basename.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--cleanpath.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--dirname.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--get_agg.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--get_bvar.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--get_dvar.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--index.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--inet_ntoa.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--inet_ntoa6.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--link_ntop.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--lltostr.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--mutex_owned.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--mutex_owner.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--progenyof.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--probe_error.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--rindex.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--rw_iswriter.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--rw_read_held.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--rw_write_held.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--speculation.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--strchr.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--strcmp.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--strjoin.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--strlen.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--strrchr.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--strtok.o /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/bpf--substr.o
bpf-unknown-none-ld: cannot open output file /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/dlibs/bpf_dlib.o: No such file or directory
make: *** [Makerules:23: /var/tmp/portage/dev-debug/dtrace-9999/work/dtrace-9999/build/dlibs/bpf_dlib.o] Error 1
 * ERROR: dev-debug/dtrace-9999::gentoo failed (compile phase):
 *   emake failed

I'm going to try hit it with make --shuffle to get a seed. Full log attached: build.log.gz.

Start with Makerules:23 and inspect the target that creates build/dlibs/bpf_dlib.o. Use the attached build.log.gz and try reproducing the race with make --shuffle; done means highly parallel builds reliably create the output without the missing-directory failure.