Add missing Fanotify APIs from the libc crate into Nix. #1629

Job	Run time
macos	3m 36s
macos-aarch64	1m 25s
linux_native_builds (x86_64-unknown-linux-gnu)	6h 0m 14s
linux_native_builds (x86_64-unknown-linux-musl)	6h 0m 13s
minver	12s
rust_stable	6h 0m 13s
rustfmt	13s
solaris (x86_64-pc-solaris)	4m 18s
tier3 (x86_64-unknown-dragonfly)	58s
tier3 (x86_64-unknown-openbsd)	1m 1s
tier3 (x86_64-unknown-haiku)	1m 9s
tier3 (armv7-unknown-linux-uclibceabihf)	1m 8s
cross_compiling	0s
cross	0s
redox	0s
	18h 14m 40s

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