proc/native: move Thread.running to os struct

Windows and macOS aren't using this field so move it to the os-specific
thread struct and remove it from everything except linux.

pkg/proc/native/proc_darwin.go

@@ -435,7 +435,6 @@ func (dbp *Process) stop(trapthread *Thread) (err error) {
 				return dbp.exitGuard(err)
 			}
 		}
-		th.running = false
 	}
 
 	ports, err := dbp.waitForStop()

pkg/proc/native/proc_linux.go

@@ -240,8 +240,8 @@ func (dbp *Process) trapWait(pid int) (*Thread, error) {
 			dbp.haltMu.Unlock()
 			if halt {
 				dbp.halt = false
-				th.running = false
-				dbp.threads[int(wpid)].running = false
+				th.os.running = false
+				dbp.threads[int(wpid)].os.running = false
 				return nil, nil
 			}
 			if err = th.Continue(); err != nil {
@@ -267,12 +267,12 @@ func (dbp *Process) trapWait(pid int) (*Thread, error) {
 		halt := dbp.halt
 		dbp.haltMu.Unlock()
 		if halt && (status.StopSignal() == sys.SIGTRAP || status.StopSignal() == sys.SIGSTOP) {
-			th.running = false
+			th.os.running = false
 			dbp.halt = false
 			return th, nil
 		}
 		if status.StopSignal() == sys.SIGTRAP {
-			th.running = false
+			th.os.running = false
 			return th, nil
 		}
 		if th != nil {
@@ -425,7 +425,7 @@ func (dbp *Process) stop(trapthread *Thread) (err error) {
 	for {
 		allstopped := true
 		for _, th := range dbp.threads {
-			if th.running {
+			if th.os.running {
 				allstopped = false
 				break
 			}

pkg/proc/native/proc_windows.go

@@ -404,7 +404,6 @@ func (dbp *Process) resume() error {
 	}
 
 	for _, thread := range dbp.threads {
-		thread.running = true
 		_, err := _ResumeThread(thread.os.hThread)
 		if err != nil {
 			return err
@@ -419,9 +418,6 @@ func (dbp *Process) stop(trapthread *Thread) (err error) {
 	if dbp.exited {
 		return &proc.ProcessExitedError{Pid: dbp.Pid()}
 	}
-	for _, th := range dbp.threads {
-		th.running = false
-	}
 
 	// While the debug event that stopped the target was being propagated
 	// other target threads could generate other debug events.
@@ -439,7 +435,6 @@ func (dbp *Process) stop(trapthread *Thread) (err error) {
 	}
 
 	for _, thread := range dbp.threads {
-		thread.running = false
 		_, err := _SuspendThread(thread.os.hThread)
 		if err != nil {
 			return err

pkg/proc/native/threads.go

@@ -18,7 +18,6 @@ type Thread struct {
 
 	dbp            *Process
 	singleStepping bool
-	running        bool
 	os             *OSSpecificDetails
 }
 
@@ -49,11 +48,9 @@ func (thread *Thread) Continue() error {
 // execute the instruction, and then replace the breakpoint.
 // Otherwise we simply execute the next instruction.
 func (thread *Thread) StepInstruction() (err error) {
-	thread.running = true
 	thread.singleStepping = true
 	defer func() {
 		thread.singleStepping = false
-		thread.running = false
 	}()
 	pc, err := thread.PC()
 	if err != nil {

pkg/proc/native/threads_darwin.go

@@ -69,7 +69,6 @@ func (t *Thread) singleStep() error {
 }
 
 func (t *Thread) resume() error {
-	t.running = true
 	// TODO(dp) set flag for ptrace stops
 	var err error
 	t.dbp.execPtraceFunc(func() { err = PtraceCont(t.dbp.pid, 0) })

pkg/proc/native/threads_linux.go

@@ -14,6 +14,7 @@ type WaitStatus sys.WaitStatus
 // process details.
 type OSSpecificDetails struct {
 	registers sys.PtraceRegs
+	running   bool
 }
 
 func (t *Thread) halt() (err error) {
@@ -37,7 +38,7 @@ func (t *Thread) resume() error {
 }
 
 func (t *Thread) resumeWithSig(sig int) (err error) {
-	t.running = true
+	t.os.running = true
 	t.dbp.execPtraceFunc(func() { err = PtraceCont(t.ID, sig) })
 	return
 }

pkg/proc/native/threads_windows.go

@@ -86,7 +86,6 @@ func (t *Thread) singleStep() error {
 }
 
 func (t *Thread) resume() error {
-	t.running = true
 	var err error
 	t.dbp.execPtraceFunc(func() {
 		//TODO: Note that we are ignoring the thread we were asked to continue and are continuing the