[Media_api] Windows midiOutLongMsg strangeness

[Roger Dannenberg]

Ben,
    That's a good idea, but putting midiOutPrepareHeader() before or 
after the modifications to the MIDIHDR makes no difference, at least in 
my tests. So with midiOutPrepareHeader() in place, sysexs sends to MIDI 
Yoke virtual midi ports only work if I copy the sysex message 
(hdr->lpData) to a freshly allocated block on the heap. Sysex sends to 
my MidiMan 1x1 interface work (at least in my latest tests) using the 
same code but without the memory copy. -Roger

 > When you change where lpData points to, you fiddle with whatever "magic"
 > happens you call midiOutPrepareHeader or midiInPrepareHeader.