bug#10736: Add "underwave" face attribute

[Jan Djärv]

Hello.

12 apr 2012 kl. 23:57 skrev Stefan Monnier:

>> Looking at the mailing list, it seems like it was agreed that this is
>> useful, and that this interface is correct.  Since we're in Emacs 24.2
>> territory now, should this go in?
> 
> Assuming the code is OK, yes.   I'd like to hear someone's opinion on
> the code, tho (Jan, maybe?).
> 

Looks OK.  In general I don't like the "Get GC values, change some GC value, 
draw, restore changed GC value" technique. It is better to create more GC:s.  
But the new code just mimics the old, so it is nothing particular for this 
patch.

        Jan D.