Find right hg command for detached process On Windows, Mercurial can be run from the python script of from a frozen executable. In the first case, we have to call the python interpreter since the script is not executable. Frozen executable can be called directly. Fix 3/3 for issue421

--- a/mercurial/windows.py
+++ b/mercurial/windows.py
@@ -352,6 +352,9 @@
         STARTUPINFO())
     return pid
 
+def gethgcmd():
+    return [sys.executable] + sys.argv[:1]
+
 try:
     # override functions with win32 versions if possible
     from win32 import *