Weaklink most toolbox modules, improving backward compatibility. Modules will no longer fail to load if a single routine is missing on the curent OS version, in stead calling the missing routine will raise an exception.

Should finally fix 531398. 2.2.1 candidate.

Also blacklisted some constants with definitions that were not Python-compatible.
diff --git a/Mac/Modules/cf/cfscan.py b/Mac/Modules/cf/cfscan.py
index 3e09df4..be11dba 100644
--- a/Mac/Modules/cf/cfscan.py
+++ b/Mac/Modules/cf/cfscan.py
@@ -95,6 +95,7 @@
 			"CFStringCreateMutableWithExternalCharactersNoCopy", # Not a clue...
 			"CFStringSetExternalCharactersNoCopy",
 			"CFStringGetCharacterAtIndex", # No format for single unichars yet.
+			"kCFStringEncodingInvalidId", # incompatible constant declaration
 			]
 
 	def makegreylist(self):