Add all built-in variables for all versions/profiles/stages of GLSL. Also, made more readable; declarations are cut and paste from the specs, with quotes around them. This does not include built-in constants yet (other than MaxClipDistances), just the non-constants.

git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@23551 e7fa87d3-cd2b-0410-9028-fcbf551c1848

Test/120.vert

@@ -17,6 +17,9 @@ void main()
     centTexCoord = attv2; 
     gl_Position = attv4;
 
+    gl_ClipVertex = attv4;
+    gl_ClipDistance[1] = 0.2;  // ERROR
+
     vec3[12] a;
     vec4[a.length()] b;
     gl_Position = b[b.length()-1];