--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -968,6 +968,12 @@ if os.name == 'nt':
                     return p_name_ext
         return default
 
+    def set_signal_handler():
+        try:
+            set_signal_handler_win32()
+        except NameError:
+            pass
+
     try:
         # override functions with win32 versions if possible
         from util_win32 import *

--- a/mercurial/util_win32.py
+++ b/mercurial/util_win32.py
@@ -300,7 +300,7 @@ class posixfile_nt(object):
 
 getuser_fallback = win32api.GetUserName
 
-def set_signal_handler():
+def set_signal_handler_win32():
     """Register a termination handler for console events including
     CTRL+C. python signal handlers do not work well with socket
     operations.