diff --git a/site_scons/buildutils.py b/site_scons/buildutils.py
index e0862d2a6..0e7422790 100644
--- a/site_scons/buildutils.py
+++ b/site_scons/buildutils.py
@@ -555,7 +555,7 @@ def getSpawn(env):
     Adapted from http://www.scons.org/wiki/LongCmdLinesOnWin32
     """
 
-    if 'cmd.exe' not in env['SHELL'] or env['CXX'] == 'cl':
+    if 'cmd.exe' not in env['SHELL'] or env.subst('$CXX') == 'cl':
         return env['SPAWN']
 
     try: