Fixes for build warnings on macOS with latest toolchain #5342

Job	Run time
build-ubuntu-latest-minimal-clang	2m 49s
build-ubuntu-latest-full-featured-gcc	1m 17s
build-ubuntu-latest-full-featured-clang	2m 58s
build-macos-latest-clang	48s
build-ubuntu-latest-minimal-gcc	27s
build-ubuntu-latest-pcp	46s
build-unsupported-latest-gcc	33s
build-dragonflybsd-latest-gcc	2m 50s
build-ubuntu-latest-gcc-static	1m 11s
build-ubuntu-latest-clang-analyzer	2m 49s
build-openbsd-latest-clang	2m 46s
build-freebsd-latest-clang	2m 10s
build-netbsd-latest-gcc	2m 54s
build-ubuntu-latest-clang-sanitizer	1m 25s
lint-pcp-config	4s
lint-whitespace	4s
build-solaris-latest-gcc	4m 36s
	30m 27s

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