diff -r 3ce0102e4c1f Lib/site.py
--- a/Lib/site.py	Wed Oct 09 14:53:01 2013 +0200
+++ b/Lib/site.py	Wed Oct 09 15:26:23 2013 +0200
@@ -70,7 +70,6 @@
 
 import sys
 import os
-import re
 import builtins
 import _sitebuiltins
 
@@ -436,11 +435,10 @@
                 encodings._cache[enc] = encodings._unknown
                 encodings.aliases.aliases[enc] = 'mbcs'
 
-
-CONFIG_LINE = re.compile(r'^(?P<key>(\w|[-_])+)\s*=\s*(?P<value>.*)\s*$')
+CONFIG_LINE = None
 
 def venv(known_paths):
-    global PREFIXES, ENABLE_USER_SITE
+    global PREFIXES, ENABLE_USER_SITE, CONFIG_LINE
 
     env = os.environ
     if sys.platform == 'darwin' and '__PYVENV_LAUNCHER__' in env:
@@ -460,6 +458,10 @@
         ]
 
     if candidate_confs:
+        if CONFIG_LINE is None:
+            import re
+            CONFIG_LINE = re.compile(r'^(?P<key>(\w|[-_])+)\s*'
+                                     r'=\s*(?P<value>.*)\s*$')
         virtual_conf = candidate_confs[0]
         system_site = "true"
         with open(virtual_conf) as f: