mesa: add missing FEATURE_attrib_stack around
      call to _mesa_free_attrib_data()
diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
index 96a8c30..564139a 100644
--- a/src/mesa/main/context.c
+++ b/src/mesa/main/context.c
@@ -1316,7 +1316,9 @@
    _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current, NULL);
    _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._TexEnvProgram, NULL);
 
+#if FEATURE_attrib_stack
    _mesa_free_attrib_data(ctx);
+#endif
    _mesa_free_lighting_data( ctx );
 #if FEATURE_evaluators
    _mesa_free_eval_data( ctx );