Update to SCons 1.2.0.

third_party/scons/scons-local/SCons/compat/_scons_subprocess.py

 # subprocess - Subprocesses with accessible I/O streams
 #
 # For more information about this module, see PEP 324.
 #
 # This module should remain compatible with Python 2.2, see PEP 291.
 #
 # Copyright (c) 2003-2005 by Peter Astrand <astrand@lysator.liu.se>
 #
 # Licensed to PSF under a Contributor Agreement.
 # See http://www.python.org/2.4/license for licensing details.
@@ skipping 376 matching lines @@
                              STD_OUTPUT_HANDLE, STD_ERROR_HANDLE
         from win32api import GetCurrentProcess, DuplicateHandle, \
                              GetModuleFileName, GetVersion
         from win32con import DUPLICATE_SAME_ACCESS, SW_HIDE
         from win32pipe import CreatePipe
         from win32process import CreateProcess, STARTUPINFO, \
                                  GetExitCodeProcess, STARTF_USESTDHANDLES, \
                                  STARTF_USESHOWWINDOW, CREATE_NEW_CONSOLE
         from win32event import WaitForSingleObject, INFINITE, WAIT_OBJECT_0
     else:
-        from _subprocess import *
+        # SCons:  don't die on Python versions that don't have _subprocess.
+        try:
+            from _subprocess import *
+        except ImportError:
+            pass
         class STARTUPINFO:
             dwFlags = 0
             hStdInput = None
             hStdOutput = None
             hStdError = None
             wShowWindow = 0
         class pywintypes:
             error = IOError
 else:
     import select
@@ skipping 869 matching lines @@
     print "Executing calc..."
     p = Popen("calc")
     p.wait()
 
 
 if __name__ == "__main__":
     if mswindows:
         _demo_windows()
     else:
         _demo_posix()