Allow the pre-150 built-in redeclarations when using SSO: gl_Position, gl_PointSize, gl_ClipVertex, and gl_FogFragCoord.


git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@26399 e7fa87d3-cd2b-0410-9028-fcbf551c1848