windows: add Thread32{First,Next} funcions

ref:
https://docs.microsoft.com/en-us/windows/desktop/api/tlhelp32/nf-tlhelp32-thread32first
https://docs.microsoft.com/en-us/windows/desktop/api/tlhelp32/nf-tlhelp32-thread32next
https://docs.microsoft.com/en-us/windows/desktop/api/tlhelp32/ns-tlhelp32-tagthreadentry32

Update #32404

Change-Id: I6c8150d1077cf1e8abd0b06403313fef01f4b6e4
Reviewed-on: https://go-review.googlesource.com/c/sys/+/180918
Reviewed-by: Marc-Antoine Ruel <maruel@chromium.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

windows/syscall_windows.go

@@ -243,6 +243,8 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	CreateToolhelp32Snapshot(flags uint32, processId uint32) (handle Handle, err error) [failretval==InvalidHandle] = kernel32.CreateToolhelp32Snapshot
 //sys	Process32First(snapshot Handle, procEntry *ProcessEntry32) (err error) = kernel32.Process32FirstW
 //sys	Process32Next(snapshot Handle, procEntry *ProcessEntry32) (err error) = kernel32.Process32NextW
+//sys	Thread32First(snapshot Handle, threadEntry *ThreadEntry32) (err error)
+//sys	Thread32Next(snapshot Handle, threadEntry *ThreadEntry32) (err error)
 //sys	DeviceIoControl(handle Handle, ioControlCode uint32, inBuffer *byte, inBufferSize uint32, outBuffer *byte, outBufferSize uint32, bytesReturned *uint32, overlapped *Overlapped) (err error)
 // This function returns 1 byte BOOLEAN rather than the 4 byte BOOL.
 //sys	CreateSymbolicLink(symlinkfilename *uint16, targetfilename *uint16, flags uint32) (err error) [failretval&0xff==0] = CreateSymbolicLinkW

windows/types_windows.go

@@ -659,6 +659,16 @@ type ProcessEntry32 struct {
 	ExeFile         [MAX_PATH]uint16
 }
 
+type ThreadEntry32 struct {
+	Size           uint32
+	Usage          uint32
+	ThreadID       uint32
+	OwnerProcessID uint32
+	BasePri        int32
+	DeltaPri       int32
+	Flags          uint32
+}
+
 type Systemtime struct {
 	Year         uint16
 	Month        uint16

windows/zsyscall_windows.go

@@ -182,6 +182,8 @@ var (
 	procCreateToolhelp32Snapshot           = modkernel32.NewProc("CreateToolhelp32Snapshot")
 	procProcess32FirstW                    = modkernel32.NewProc("Process32FirstW")
 	procProcess32NextW                     = modkernel32.NewProc("Process32NextW")
+	procThread32First                      = modkernel32.NewProc("Thread32First")
+	procThread32Next                       = modkernel32.NewProc("Thread32Next")
 	procDeviceIoControl                    = modkernel32.NewProc("DeviceIoControl")
 	procCreateSymbolicLinkW                = modkernel32.NewProc("CreateSymbolicLinkW")
 	procCreateHardLinkW                    = modkernel32.NewProc("CreateHardLinkW")
@@ -1929,6 +1931,30 @@ func Process32Next(snapshot Handle, procEntry *ProcessEntry32) (err error) {
 	return
 }
 
+func Thread32First(snapshot Handle, threadEntry *ThreadEntry32) (err error) {
+	r1, _, e1 := syscall.Syscall(procThread32First.Addr(), 2, uintptr(snapshot), uintptr(unsafe.Pointer(threadEntry)), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func Thread32Next(snapshot Handle, threadEntry *ThreadEntry32) (err error) {
+	r1, _, e1 := syscall.Syscall(procThread32Next.Addr(), 2, uintptr(snapshot), uintptr(unsafe.Pointer(threadEntry)), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
 func DeviceIoControl(handle Handle, ioControlCode uint32, inBuffer *byte, inBufferSize uint32, outBuffer *byte, outBufferSize uint32, bytesReturned *uint32, overlapped *Overlapped) (err error) {
 	r1, _, e1 := syscall.Syscall9(procDeviceIoControl.Addr(), 8, uintptr(handle), uintptr(ioControlCode), uintptr(unsafe.Pointer(inBuffer)), uintptr(inBufferSize), uintptr(unsafe.Pointer(outBuffer)), uintptr(outBufferSize), uintptr(unsafe.Pointer(bytesReturned)), uintptr(unsafe.Pointer(overlapped)), 0)
 	if r1 == 0 {