os.fork raises AttributeError, not NameError, if fork() isn't
supported.  Pointed out by Moshe Zadka <moshez@math.huji.ac.il>.
diff --git a/Lib/CGIHTTPServer.py b/Lib/CGIHTTPServer.py
index dc17392..fa30cbd 100644
--- a/Lib/CGIHTTPServer.py
+++ b/Lib/CGIHTTPServer.py
@@ -21,7 +21,7 @@
 
 try:
     os.fork
-except NameError:
+except AttributeError:
     raise SystemError, __name__ + " requires os.fork()"