diff -r e1dfecfcfa04 Lib/site.py
--- a/Lib/site.py	Mon Nov 07 23:15:10 2016 -0500
+++ b/Lib/site.py	Tue Nov 08 13:44:21 2016 +0100
@@ -422,13 +422,12 @@
 
     sys.__interactivehook__ = register_readline
 
-CONFIG_LINE = r'^(?P<key>(\w|[-_])+)\s*=\s*(?P<value>.*)\s*$'
+
 
 def venv(known_paths):
     global PREFIXES, ENABLE_USER_SITE
 
-    env = os.environ
-    if sys.platform == 'darwin' and '__PYVENV_LAUNCHER__' in env:
+    if sys.platform == 'darwin' and '__PYVENV_LAUNCHER__' in os.environ:
         executable = os.environ['__PYVENV_LAUNCHER__']
     else:
         executable = sys.executable
@@ -445,8 +444,6 @@
         ]
 
     if candidate_confs:
-        import re
-        config_line = re.compile(CONFIG_LINE)
         virtual_conf = candidate_confs[0]
         system_site = "true"
         # Issue 25185: Use UTF-8, as that's what the venv module uses when
@@ -454,10 +451,10 @@
         with open(virtual_conf, encoding='utf-8') as f:
             for line in f:
                 line = line.strip()
-                m = config_line.match(line)
-                if m:
-                    d = m.groupdict()
-                    key, value = d['key'].lower(), d['value']
+                line_fields = line.split('=', 1)
+                if len(line_fields) == 2:
+                    key = line_fields[0].rstrip().lower()
+                    value = line_fields[1].lstrip()
                     if key == 'include-system-site-packages':
                         system_site = value.lower()
                     elif key == 'home':