File libpng16-adjustment.patch of Package racket

From f97a7cf1778b74e9f38d97db61e91956565180c3 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Wed, 15 May 2013 20:38:40 -0600
Subject: [PATCH] libpng adjustment

Keep error if no "libpng" is found.
---
 collects/racket/draw/unsafe/png.rkt | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/collects/racket/draw/unsafe/png.rkt b/collects/racket/draw/unsafe/png.rkt
index a6b028d..f57de38 100644
--- a/collects/racket/draw/unsafe/png.rkt
+++ b/collects/racket/draw/unsafe/png.rkt
@@ -12,10 +12,9 @@
    ;; variants often have just "libpng", etc.
    (let loop ([alts '(("libpng16" ("16" ""))
                       ("libpng15" ("15" ""))
-                      ("libpng12" ("0" ""))
-                      ("libpng"))])
+                      ("libpng12" ("0" "")))])
      (cond
-      [(null? alts) #f]
+      [(null? alts) (ffi-lib "libpng")]
       [else (apply ffi-lib (car alts)
                    #:fail (lambda ()
                             (loop (cdr alts))))]))]
-- 
1.8.2.3