gl_VertexID implementation

This cl implements support for gl_VertexID.

Passes the functional.shaders.builtin_variable.vertex_id test.

Change-Id: I5550e3ecba30e29f1e38ace608d730833a1e9598
Reviewed-on: https://swiftshader-review.googlesource.com/10958
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/src/Shader/VertexPipeline.cpp b/src/Shader/VertexPipeline.cpp
index 8db3ca0..8792884 100644
--- a/src/Shader/VertexPipeline.cpp
+++ b/src/Shader/VertexPipeline.cpp
@@ -158,7 +158,7 @@
 		return dst;
 	}
 
-	void VertexPipeline::pipeline()
+	void VertexPipeline::pipeline(UInt &index)
 	{
 		Vector4f position;
 		Vector4f normal;