Only try to wrap the fd in a socket on Windows (#498)

Signed-off-by: Ivan Santiago Paunovic <ivanpauno@ekumenlabs.com>

launch/launch/utilities/signal_management.py

@@ -17,6 +17,7 @@
 import asyncio
 from contextlib import ExitStack
 import os
+import platform
 import signal
 import socket
 import threading
@@ -26,11 +27,6 @@
 from typing import Tuple  # noqa: F401
 from typing import Union
 
-try:
-    _WindowsError = WindowsError
-except NameError:
-    _WindowsError = None
-
 
 class AsyncSafeSignalManager:
     """
@@ -190,12 +186,12 @@ def __chain_wakeup_handle(self, wakeup_handle):
         if isinstance(prev_wakeup_handle, socket.socket):
             # Detach (Windows) socket and retrieve the raw OS handle.
             prev_wakeup_handle = prev_wakeup_handle.detach()
-        if wakeup_handle != -1:
+        if wakeup_handle != -1 and platform.system() == 'Windows':
             # On Windows, os.write will fail on a WinSock handle. There is no WinSock API
             # in the standard library either. Thus we wrap it in a socket.socket instance.
             try:
                 wakeup_handle = socket.socket(fileno=wakeup_handle)
-            except _WindowsError as e:
+            except WindowsError as e:
                 if e.winerror != 10038:  # WSAENOTSOCK
                     raise
         self.__prev_wakeup_handle = wakeup_handle