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/htmlrender/htmlscan.py b/Mac/Modules/htmlrender/htmlscan.py
index ff2de32..81f107c 100644
--- a/Mac/Modules/htmlrender/htmlscan.py
+++ b/Mac/Modules/htmlrender/htmlscan.py
@@ -19,6 +19,8 @@
 	scanner = MyScanner(input, output, defsoutput)
 	scanner.scan()
 	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! ==="