glsl: Optionally lower TES gl_PatchVerticesIn to a uniform.

i965 has no special hardware for this, so we need to pass this value in
as a uniform (unless the TES is linked against a TCS, in which case the
linker can just replace this with a constant).

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Cc: mesa-stable@lists.freedesktop.org

src/mesa/program/prog_statevars.c

@@ -598,6 +598,13 @@ _mesa_fetch_state(struct gl_context *ctx, const gl_state_index state[],
          }
          return;
 
+      case STATE_TES_PATCH_VERTICES_IN:
+         if (ctx->TessCtrlProgram._Current)
+            val[0].i = ctx->TessCtrlProgram._Current->VerticesOut;
+         else
+            val[0].i = ctx->TessCtrlProgram.patch_vertices;
+         return;
+
       /* XXX: make sure new tokens added here are also handled in the 
        * _mesa_program_state_flags() switch, below.
        */