osxkeychain: fix build with Rust #28577

Job	Run time
config	8s
fuzz smoke test	1m 11s
win build	5m 2s
static-analysis	6m 7s
win+Meson build	4m 37s
documentation	7m 20s
sparse	3m 22s
rust-analysis	1m 29s
osx-reftable (macos-14)	35m 17s
osx-clang (macos-14)	6h 0m 16s
osx-meson (macos-14)	51m 45s
osx-gcc (macos-14)	45m 6s
win+VS build	0s
fedora-breaking-changes-meson (fedora:latest)	18m 11s
linux-leaks (ubuntu:rolling)	48m 51s
linux-asan-ubsan (ubuntu:rolling)	1h 10m 11s
linux-meson (ubuntu:rolling)	24m 59s
linux-musl-meson (alpine:latest)	21m 11s
linux-reftable-leaks (ubuntu:rolling)	47m 42s
debian-11 (debian:11)	21m 56s
almalinux-8 (almalinux:8)	20m 41s
linux-reftable (ubuntu:rolling)	24m 6s
linux-TEST-vars (ubuntu:20.04)	27m 48s
linux32 (i386/ubuntu:20.04)	6h 0m 3s
linux-sha256 (ubuntu:rolling)	28m 56s
linux-breaking-changes (ubuntu:rolling)	22m 27s
win+VS test	0s
win+Meson test (9)	6m 27s
win+Meson test (8)	10m 59s
win+Meson test (7)	9m 1s
win+Meson test (2)	46m 50s
win+Meson test (5)	8m 35s
win+Meson test (1)	7m 58s
win+Meson test (3)	10m 40s
win+Meson test (0)	9m 29s
win+Meson test (4)	7m 55s
win+Meson test (6)	12m 5s
win test (7)	7m 53s
win test (6)	10m 14s
win test (1)	7m 8s
win test (8)	6m 12s
win test (3)	10m 42s
win test (0)	12m 42s
win test (4)	58m 58s
win test (5)	16m 44s
win test (9)	6m 20s
win test (2)	7m 40s
	1d 1h 33m 14s

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