Improve the spa_ump_to_midi function so that it can consume multiple UMP
messages and produce multiple midi messages.
Some UMP messages (like program changes) need to be translated into up
to 3 midi messages. Do this byt adding a state to the function and by
making it consume the input bytes, just like the spa_ump_from_midi
function.
Adapt code to this new world. This is a little API break..
The midi events have their large data offsets relative to the start of
the buffer and the large data is at the end of the buffer. Because we
copied it down, right after the events, but we didn't adjust the
offsets, calculate a correction offset when unpacking the events.
SysEx in UMP can span multiple packets. In MIDI1 we can't split them up
into multiple events so we need to collect the complete sysex and then
write out the event.
Fixes SysEx writes to ALSA seq by running the event encoder until a
valid packet is completed.
Also fixes split MIDI1 packets in the JACK API when going through the
tunnel or via netjack.
This provides access to GNU C library-style endian and byteswap functions.
Windows doesn't provide pre-processor defines for endianness, but
all current Windows architectures (X32, X64, ARM) are little-endian.
The module advertizes itself on multicast and will trigger a new client
in the netjack2 manager. Tested with jack2 and 'jack_load netmanager'.
The driver will receive and send data (no midi yet) from and to the
manager in sync with the manager, without resampling and with a fixed
latency.
