[Media_api] New PortMidi release

[Roger Dannenberg]

 > For what it worth, this version do not compile out of the box in the
 > case NEWBUFFER is not defined.

Right. My modifications dealing with overflow handling and reporting 
intersect with the NEWBUFFER code, so undefining NEWBUFFER would likely 
reactivate some bugs. Therefore, I think the requirement to compile with 
NEWBUFFER is a feature. I guess I should have changed so the requirement 
is to compile without OLDBUFFER. I'll either do this or just remove the 
old code soon.

-Roger