macdrv: implement getting and setting the screen saver state, version 4

[Ken Thomases]

Hi,

On Jan 21, 2013, at 6:21 PM, C.W. Betts wrote:

> This version falls through in SPI_SETSCREENSAVEACTIVE.

Sadly, you used C++ style for the fall-through comment. :-/

Also, you have some trailing whitespace and the patch no longer applies cleanly after today's commits of mine.  It should be easy to fix that though.  There aren't any serious conflicts.

-Ken