Cycles: Oren-Nayar BSDF support. This is not a separate shader node, rather it

is available through the Roughness input on the Diffuse BSDF.
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/Shaders#Diffuse

Patch by Yasuhiro Fujii, thanks!

intern/cycles/render/nodes.cpp

@@ -1003,11 +1003,12 @@ void VelvetBsdfNode::compile(OSLCompiler& compiler)
 DiffuseBsdfNode::DiffuseBsdfNode()
 {
 	closure = CLOSURE_BSDF_DIFFUSE_ID;
+	add_input("Roughness", SHADER_SOCKET_FLOAT, 0.0f);
 }
 
 void DiffuseBsdfNode::compile(SVMCompiler& compiler)
 {
-	BsdfNode::compile(compiler, NULL, NULL);
+	BsdfNode::compile(compiler, input("Roughness"), NULL);
 }
 
 void DiffuseBsdfNode::compile(OSLCompiler& compiler)