GLSL has started to remove deprecated keywords such as 'attribute' and 'varying' and replaced them with in/out. Since the OpenGL states can't be accessed in new GLSL versions shaders have to bind with ogre like HLSL. The only way to bind right now is for ogre to scan the shader source for 'entry' points such as "attribute vec4 vertex".
This patch correctly parses the source looking for both...
