better regexp use

svn: r6057

collects/net/doc.txt

@@ -204,13 +204,13 @@ PROCEDURES -----------------------------------------------------------
   The "head.ss" library provides procedures, such as `extract-field,
   for manipulating the header.
 
-  Since web server sometimes return mis-formatted replies,
+  Since web servers sometimes return mis-formatted replies,
   `purify-port' is liberal in what it accepts as a header. as a
   result, the result string may be ill formed, but it will either be
   the empty string, or it will be a string matching the following
   regexp:
 
-      #rx"^HTTP/.*?((\r\n\r\n)|(\n\n)|(\r\r))"
+      #rx"^HTTP/.*?(\r\n\r\n|\n\n|\r\r)"
 
 > (call/input-url url url->port-proc port->X-proc [list-of-strings]) -> X
 

collects/net/url-unit.ss

@@ -312,7 +312,7 @@
     ;; purify-port : in-port -> header-string
     (define (purify-port port)
       (let ([m (regexp-match-peek-positions
-                #rx"^HTTP/.*?((\r\n\r\n)|(\n\n)|(\r\r))" port)])
+                #rx"^HTTP/.*?(?:\r\n\r\n|\n\n|\r\r)" port)])
         (if m (read-string (cdar m) port) "")))
 
     (define character-set-size 256)