const golang.org/x/sys/unix.TIOCSDRAINWAIT

one use

	golang.org/x/sys/unix (current package)
		zerrors_darwin_arm64.go#L1427: 	TIOCSDRAINWAIT                    = 0x80047457

The pages are generated with Golds v0.2.8-preview. (GOOS=darwin GOARCH=arm64)