Add deprecation warning to 'pre' module

Lib/pre.py

@@ -87,6 +87,12 @@ This module also defines an exception 'error'.
 import sys
 from pcre import *
 
+# XXX This module is deprecated as of Python 2.3, and should be removed
+# in the version that follows 2.3.
+import warnings as _warnings
+_warnings.warn("Please use the 're' module, not the 'pre' module",
+               DeprecationWarning)
+			     
 __all__ = ["match","search","sub","subn","split","findall","escape","compile",
            "I","L","M","S","X","IGNORECASE","LOCALE","MULTILINE","DOTALL",
            "VERBOSE","error"]