Add missing Fanotify APIs from the libc crate into Nix. #1736

Job	Run time
macos-aarch64	2m 11s
minver	12s
macos	3m 41s
linux_native_builds (x86_64-unknown-linux-gnu)	36s
linux_native_builds (x86_64-unknown-linux-musl)	43s
rustfmt	3s
solaris (x86_64-pc-solaris)	4m 40s
rust_stable	26s
tier3 (x86_64-unknown-dragonfly)	1m 5s
tier3 (x86_64-unknown-openbsd)	1m 6s
tier3 (x86_64-unknown-haiku)	1m 1s
tier3 (armv7-unknown-linux-uclibceabihf)	43s
tier3 (i686-unknown-hurd-gnu)	59s
cross	0s
redox	0s
cross_compiling	0s
	17m 26s

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