frontend: fix build
support mp3 decoding over libavcodec
avoid link-time dependency to libavcodec

it has lots of lots of deps, and we want to run on barebone systems
32x: adjust sh2 cycles again

MK2 doesn't play it's animations if slave is clocked too slow..
the more we underclock slave, the more often animations get stuck
Why does it need so many cycles?
32x: fix lockstep code
don't crash on bad timing
32x: start reworking sheduling
32x: rework scheduling/timing

- don't run in line quantity
- decouple from 68k
- some things to tune..
32x: add some comments
save event times to savestates
32x: a hack for dealing with pwm inaccuracy
drc: reload cycles after memhandlers