glsl: Set gl_MaxVertexOutputs from VertexProgram.MaxOutputComponents etc

glsl: Set gl_MaxVertexOutputs from VertexProgram.MaxOutputComponents etc

gl_MaxVertexOutputVectors => ctx->Const.VertexProgram.MaxOutputComponents
gl_MaxFragmentInputVectors => ctx->Const.FragmentProgram.MaxInputComponents

v2: Add types so that the code compiles.  Pointed out by Brian.

v3: Leave gl_MaxVaryingFloats et al. as-is.  Suggested by Paul.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Brian Paul <brianp@vmware.com> [v2]
Reviewed-by: Marek Olšák <marek.olsak@amd.com> [v2]
Reviewed-by: Paul Berry <stereotype441@gmail.com> [v2]