Add support for sendmmsg/recvmmsg #1014

Job	Run time
Clippy	22s
Check (armv7-sony-vita-newlibeabihf)	30s
Check (i686-unknown-hurd-gnu)	31s
Docs (aarch64-apple-ios)	14s
Check (aarch64-apple-ios)	34s
Docs (armv7-sony-vita-newlibeabihf)	28s
Docs (aarch64-linux-android)	12s
Check (aarch64-linux-android)	8s
Rustfmt	7s
Docs (i686-unknown-hurd-gnu)	28s
Docs (x86_64-apple-darwin)	15s
Check (x86_64-apple-darwin)	24s
Docs (x86_64-unknown-fuchsia)	16s
Check (x86_64-unknown-fuchsia)	13s
Test (stable)	30s
Docs (x86_64-pc-windows-msvc)	13s
Check (x86_64-pc-windows-msvc)	11s
Test (1.63.0)	3m 17s
Docs (x86_64-pc-solaris)	13s
Check (x86_64-pc-solaris)	11s
Test (beta)	25s
Docs (x86_64-unknown-freebsd)	13s
Check (x86_64-unknown-freebsd)	11s
Test (nightly)	24s
Docs (x86_64-unknown-illumos)	13s
Check (x86_64-unknown-illumos)	21s
Test (macos)	46s
Docs (x86_64-unknown-linux-gnu)	14s
Check (x86_64-unknown-linux-gnu)	7s
Test (windows)	55s
Docs (x86_64-unknown-linux-musl)	15s
Check (x86_64-unknown-linux-musl)	9s
Docs (x86_64-unknown-netbsd)	12s
Check (x86_64-unknown-netbsd)	10s
Docs (x86_64-unknown-redox)	13s
Check (x86_64-unknown-redox)	17s
Docs (armv7-linux-androideabi)	13s
Check (armv7-linux-androideabi)	23s
Docs (i686-linux-android)	13s
Check (i686-linux-android)	8s
	15m 19s

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