NAME
	UnLock -- Unlock a directory or file

    SYNOPSIS
	UnLock( lock )
		D1

	void UnLock(BPTR)

    FUNCTION
	The filing system lock (obtained from Lock(), DupLock(), or
	CreateDir()) is removed and deallocated.

    INPUTS
	lock - BCPL pointer to a lock

    NOTE
	passing zero to UnLock() is harmless

    SEE ALSO
	Lock(), DupLock(), ParentOfFH(), DupLockFromFH()