Implement cull distances for GLSL 4.5 (but not as an extension yet, just a 4.5 feature).

git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@27714 e7fa87d3-cd2b-0410-9028-fcbf551c1848

Test/450.geom

@@ -0,0 +1,14 @@
+#version 450 core
+
+in gl_PerVertex {
+    float gl_CullDistance[3];
+} gl_in[];
+
+out gl_PerVertex {
+    float gl_CullDistance[3];
+};
+
+void main()
+{
+    gl_CullDistance[2] = gl_in[1].gl_CullDistance[2];
+}