diff --git a/Formula/gnu-prolog.rb b/Formula/gnu-prolog.rb
index aa4fa546427..5f8fa44d28e 100644
--- a/Formula/gnu-prolog.rb
+++ b/Formula/gnu-prolog.rb
@@ -7,8 +7,9 @@ class GnuProlog < Formula
 
   # Upstream patch:
   # http://sourceforge.net/p/gprolog/code/ci/784b3443a0a2f087c1d1e7976739fa517efe6af6
-  def patches
-    "https://gist.github.com/jacknagel/7549696/raw/3078eef282ca141c95a0bf74396f4248bbe34775/gprolog-clang.patch"
+  patch do
+    url "https://gist.github.com/jacknagel/7549696/raw/3078eef282ca141c95a0bf74396f4248bbe34775/gprolog-clang.patch"
+    sha1 "8af7816a97bd1319fbd3ae52cedc02ccc9164d27"
   end
 
   def install