open-scene-graph: fails with clang

Closes Homebrew/homebrew#11348.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Formula/open-scene-graph.rb

@@ -17,6 +17,14 @@ class OpenSceneGraph < Formula
   depends_on 'librsvg' => :optional
   depends_on 'collada-dom' => :optional
 
+  fails_with :clang do
+    build 318
+    cause <<-EOS.undent
+      cannot initialize a parameter of type 'void *' with an lvalue of type 'const void *const'
+      http://forum.openscenegraph.org/viewtopic.php?t=10042
+      EOS
+  end
+
   # The mini-Boost finder in FindCOLLADA doesn't find our boost, so fix it.
   def patches
     return DATA