libev: fix memory fence on i386 under valgrind #209

Job	Run time
validate commits	0s
Generate build matrix	7s
python linting	28s
spelling	6s
bookworm - test-install	1m 35s
bookworm - 32 bit	1m 36s
noble - test-install	1m 52s
el9 - test-install	1m 41s
alpine - test-install	1m 13s
fedora40 - test-install	1m 23s
jammy - test-install	1m 24s
focal - py3.8	1m 28s
bookworm - gcc-12,content-s3,distcheck	1m 53s
fedora40 - clang-18	1m 26s
coverage	1m 48s
el8 - ascii	1m 33s
el8 - system,coverage	1m 41s
inception	1m 24s
flux-pmix check	1m 25s
flux-accounting check	1m 25s
flux-sched check	1m 21s
flux-pam check	1m 30s
Generate docker manifest	0s
	28m 19s

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