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

one use

	golang.org/x/sys/unix (current package)
		ztypes_linux.go#L4200: 	HWTSTAMP_TX_ONESTEP_SYNC = 0x2

The pages are generated with Golds v0.7.6. (GOOS=linux GOARCH=amd64)