Fix bug where basedirlist was treated as a single string

Author: mdboom

setup.cfg.template

@@ -5,7 +5,7 @@
 
 [directories]
 # Uncomment to override the default basedir in setupext.py.
-# This can be a single directory or a space-delimited list of directories.
+# This can be a single directory or a comma-delimited list of directories.
 #basedirlist = /usr
 
 [status]

setupext.py

@@ -77,7 +77,7 @@ def check_output(*popenargs, **kwargs):
         pass
 
     try:
-        options['basedirlist'] = config.get("directories", "basedirlist")
+        options['basedirlist'] = config.get("directories", "basedirlist").split(',')
     except:
         pass
 else: