x/sys/windows: add ClearCommBreak and SetCommBreak

Author: twpayne

windows/syscall_windows.go

@@ -349,12 +349,14 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	SetProcessPriorityBoost(process Handle, disable bool) (err error) = kernel32.SetProcessPriorityBoost
 //sys	GetProcessWorkingSetSizeEx(hProcess Handle, lpMinimumWorkingSetSize *uintptr, lpMaximumWorkingSetSize *uintptr, flags *uint32)
 //sys	SetProcessWorkingSetSizeEx(hProcess Handle, dwMinimumWorkingSetSize uintptr, dwMaximumWorkingSetSize uintptr, flags uint32) (err error)
+//sys	ClearCommBreak(handle Handle) (err error)
 //sys	ClearCommError(handle Handle, lpErrors *uint32, lpStat *ComStat) (err error)
 //sys	EscapeCommFunction(handle Handle, dwFunc uint32) (err error)
 //sys	GetCommState(handle Handle, lpDCB *DCB) (err error)
 //sys	GetCommModemStatus(handle Handle, lpModemStat *uint32) (err error)
 //sys	GetCommTimeouts(handle Handle, timeouts *CommTimeouts) (err error)
 //sys	PurgeComm(handle Handle, dwFlags uint32) (err error)
+//sys	SetCommBreak(handle Handle) (err error)
 //sys	SetCommMask(handle Handle, dwEvtMask uint32) (err error)
 //sys	SetCommState(handle Handle, lpDCB *DCB) (err error)
 //sys	SetCommTimeouts(handle Handle, timeouts *CommTimeouts) (err error)