(compilation-error-regexp-alist): Add regexp for Perl -w.

lisp/progmodes/compile.el

@@ -234,6 +234,10 @@ of[ \t]+\"?\\([a-zA-Z]?:?[^\":\n]+\\)\"?:" 3 2)
     ;; Sun ada (VADS, Solaris):
     ;;  /home3/xdhar/rcds_rc/main.a, line 361, char 6:syntax error: "," inserted
     ("\\([^, \n\t]+\\), line \\([0-9]+\\), char \\([0-9]+\\)[:., \(-]" 1 2 3)
+
+    ;; Perl -w:
+    ;; syntax error at automake line 922, near "':'"
+    ("\n.* at \\([^ ]+\\) line \\([0-9]+\\)," 1 2)
     )
   "Alist that specifies how to match errors in compiler output.
 Each elt has the form (REGEXP FILE-IDX LINE-IDX [COLUMN-IDX FILE-FORMAT...])