In softpipe_set_viewport() use ordinary (struct) assignment to update softpipe->viewport.

The previous memcpy() was incorrect since it only copied 4 bytes instead of 32.
With struct assignment we avoid data size errors.

src/mesa/pipe/softpipe/sp_state_clip.c

@@ -56,7 +56,7 @@ void softpipe_set_viewport( struct pipe_context *pipe,
 {
    struct softpipe_context *softpipe = softpipe_context(pipe);
 
-   memcpy(&softpipe->viewport, viewport, sizeof(viewport));
+   softpipe->viewport = *viewport; /* struct copy */
 
    /* Using tnl/ and vf/ modules is temporary while getting started.
     * Full pipe will have vertex shader, vertex fetch of its own.