tinyxml: use checksummed patches

Formula/tinyxml.rb

@@ -9,18 +9,25 @@ class Tinyxml < Formula
 
   depends_on 'cmake' => :build
 
-  def patches
   # The first two patches are taken from the debian packaging of tinyxml.
   #   The first patch enforces use of stl strings, rather than a custom string type.
   #   The second patch is a fix for incorrect encoding of elements with special characters
   #   originally posted at http://sourceforge.net/p/tinyxml/patches/51/
   # The third patch adds a CMakeLists.txt file to build a shared library and provide an install target
   #   submitted upstream as https://sourceforge.net/p/tinyxml/patches/66/
-    [
-      'http://patch-tracker.debian.org/patch/series/dl/tinyxml/2.6.2-2/enforce-use-stl.patch',
-      'http://patch-tracker.debian.org/patch/series/dl/tinyxml/2.6.2-2/entity-encoding.patch',
-      'https://gist.github.com/scpeters/6325123/raw/cfb079be67997cb19a1aee60449714a1dedefed5/tinyxml_CMakeLists.patch',
-    ]
+  patch do
+    url "http://patch-tracker.debian.org/patch/series/dl/tinyxml/2.6.2-2/enforce-use-stl.patch"
+    sha1 "a1e243c0fb2fe3ba0f1138861d781284409116e2"
+  end
+
+  patch do
+    url "http://patch-tracker.debian.org/patch/series/dl/tinyxml/2.6.2-2/entity-encoding.patch"
+    sha1 "a64b7ace370419d36d95452befd82935ef8b0221"
+  end
+
+  patch do
+    url "https://gist.github.com/scpeters/6325123/raw/cfb079be67997cb19a1aee60449714a1dedefed5/tinyxml_CMakeLists.patch"
+    sha1 "90c69322296a4144795aa66a94233a9409ff7ea5"
   end
 
   def install