diff --git a/src/runtime/os1_windows.go b/src/runtime/os1_windows.go
index a36def0ffe..7244706b92 100644
--- a/src/runtime/os1_windows.go
+++ b/src/runtime/os1_windows.go
@@ -9,6 +9,11 @@ import (
 	"unsafe"
 )
 
+// TODO(brainman): should not need those
+const (
+	_NSIG = 65
+)
+
 //go:cgo_import_dynamic runtime._AddVectoredExceptionHandler AddVectoredExceptionHandler%2 "kernel32.dll"
 //go:cgo_import_dynamic runtime._CloseHandle CloseHandle%1 "kernel32.dll"
 //go:cgo_import_dynamic runtime._CreateEventA CreateEventA%4 "kernel32.dll"
@@ -49,6 +54,8 @@ import (
 //go:cgo_import_dynamic runtime._WriteConsoleW WriteConsoleW%5 "kernel32.dll"
 //go:cgo_import_dynamic runtime._WriteFile WriteFile%5 "kernel32.dll"
 
+type stdFunction unsafe.Pointer
+
 var (
 	// Following syscalls are available on every Windows PC.
 	// All these variables are set by the Windows executable
@@ -102,6 +109,35 @@ var (
 	_ stdFunction
 )
 
+// Function to be called by windows CreateThread
+// to start new os thread.
+func tstart_stdcall(newm *m) uint32
+
+func ctrlhandler(_type uint32) uint32
+
+type mOS struct {
+	waitsema uintptr // semaphore for parking on locks
+}
+
+//go:linkname os_sigpipe os.sigpipe
+func os_sigpipe() {
+	throw("too many writes on closed pipe")
+}
+
+// Stubs so tests can link correctly. These should never be called.
+func open(name *byte, mode, perm int32) int32 {
+	throw("unimplemented")
+	return -1
+}
+func closefd(fd int32) int32 {
+	throw("unimplemented")
+	return -1
+}
+func read(fd int32, p unsafe.Pointer, n int32) int32 {
+	throw("unimplemented")
+	return -1
+}
+
 type sigset struct{}
 
 // Call a Windows function with stdcall conventions,
@@ -171,8 +207,10 @@ const (
 	currentThread  = ^uintptr(1) // -2 = current thread
 )
 
-// in sys_windows_386.s and sys_windows_amd64.s
+// in sys_windows_386.s and sys_windows_amd64.s:
 func externalthreadhandler()
+func getlasterror() uint32
+func setlasterror(err uint32)
 
 // When loading DLLs, we prefer to use LoadLibraryEx with
 // LOAD_LIBRARY_SEARCH_* flags, if available. LoadLibraryEx is not
diff --git a/src/runtime/os2_windows.go b/src/runtime/os2_windows.go
deleted file mode 100644
index a867dfeb64..0000000000
--- a/src/runtime/os2_windows.go
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package runtime
-
-func getlasterror() uint32
-func setlasterror(err uint32)
-
-// Function to be called by windows CreateThread
-// to start new os thread.
-func tstart_stdcall(newm *m) uint32
-
-func ctrlhandler(_type uint32) uint32
-
-// TODO(brainman): should not need those
-const (
-	_NSIG = 65
-)
diff --git a/src/runtime/os_windows.go b/src/runtime/os_windows.go
deleted file mode 100644
index 24b3b8cf29..0000000000
--- a/src/runtime/os_windows.go
+++ /dev/null
@@ -1,32 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package runtime
-
-import "unsafe"
-
-type mOS struct {
-	waitsema uintptr // semaphore for parking on locks
-}
-
-type stdFunction unsafe.Pointer
-
-//go:linkname os_sigpipe os.sigpipe
-func os_sigpipe() {
-	throw("too many writes on closed pipe")
-}
-
-// Stubs so tests can link correctly. These should never be called.
-func open(name *byte, mode, perm int32) int32 {
-	throw("unimplemented")
-	return -1
-}
-func closefd(fd int32) int32 {
-	throw("unimplemented")
-	return -1
-}
-func read(fd int32, p unsafe.Pointer, n int32) int32 {
-	throw("unimplemented")
-	return -1
-}