Patch by Jeff Rush:

In CGIHTTPServer.py, the list of acceptable formats is -split-
on spaces but -joined- on commas, resulting in double commas
in the joined text.  It appears harmless to my browser but
ought to be fixed anyway.

    'A, B, C' -> 'A,', 'B,', 'C,' -> 'A,,B,,C'
diff --git a/Lib/CGIHTTPServer.py b/Lib/CGIHTTPServer.py
index 24bdeef..806ef57 100644
--- a/Lib/CGIHTTPServer.py
+++ b/Lib/CGIHTTPServer.py
@@ -145,7 +145,7 @@
                 if line[:1] in string.whitespace:
                     accept.append(string.strip(line))
                 else:
-                    accept = accept + string.split(line[7:])
+                    accept = accept + string.split(line[7:], ',')
             env['HTTP_ACCEPT'] = string.joinfields(accept, ',')
             ua = self.headers.getheader('user-agent')
             if ua: