After generating the Python file with definitions try to run it, so
we catch errors during the build process in stead of later during runtime.
diff --git a/Mac/Modules/cf/cfscan.py b/Mac/Modules/cf/cfscan.py
index 0bcf914..aa0ea3d 100644
--- a/Mac/Modules/cf/cfscan.py
+++ b/Mac/Modules/cf/cfscan.py
@@ -44,6 +44,8 @@
 	scanner.scan()
 	scanner.gentypetest(SHORT+"typetest.py")
 	scanner.close()
+	print "=== Testing definitions output code ==="
+	execfile(defsoutput, {}, {})
 	print "=== Done scanning and generating, now importing the generated code... ==="
 	exec "import " + SHORT + "support"
 	print "=== Done.  It's up to you to compile it now! ==="