Fixes for build warnings on macOS with latest toolchain #5345

Job	Run time
build-ubuntu-latest-minimal-clang	3m 37s
build-ubuntu-latest-minimal-gcc	43s
build-ubuntu-latest-full-featured-clang	2m 33s
build-ubuntu-latest-clang-sanitizer	2m 48s
build-ubuntu-latest-full-featured-gcc	1m 8s
build-ubuntu-latest-pcp	56s
build-ubuntu-latest-clang-analyzer	3m 21s
build-macos-latest-clang	1m 9s
build-freebsd-latest-clang	2m 30s
build-unsupported-latest-gcc	43s
build-dragonflybsd-latest-gcc	2m 48s
build-netbsd-latest-gcc	3m 22s
build-solaris-latest-gcc	8m 12s
lint-pcp-config	4s
lint-whitespace	5s
build-openbsd-latest-clang	3m 7s
build-ubuntu-latest-gcc-static	1m 17s
	38m 23s

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