Total audio crash

[freq-mod]

Yes. Literally doing so as soon as opening furnace crashes with:
furnace: /home/anon/furnace/src/engine/blip_buf.c:210: blip_read_samples: Assertion `count >= 0' failed.
Stack trace (most recent call last) in thread 9355:
#18 Object "[0xffffffffffffffff]", at 0xffffffffffffffff, in
#17 Object "/usr/lib/libc.so.6", at 0x7faba8d10dfb, in
#16 Object "/usr/lib/libc.so.6", at 0x7faba8c8c9ea, in
#15 Object "/usr/lib/libSDL2-2.0.so.0", at 0x7faba9744c0a, in
#14 Object "/usr/lib/libSDL2-2.0.so.0", at 0x7faba96352e0, in
#13 Object "furnace", at 0x5570fbafbfd6, in taSDLProcess(void*, unsigned char*, int)
#12 Object "furnace", at 0x5570fbafc081, in TAAudioSDL::onProcess(unsigned char*, int)
#11 Object "furnace", at 0x5570fb8aaaed, in process(void*, float**, float**, int, int, unsigned int)
#10 Object "furnace", at 0x5570fb94dce3, in DivEngine::nextBuf(float**, float**, int, int, unsigned int)
#9 Object "furnace", at 0x5570fb887efc, in DivWorkPool::push(void ()(void), void*)
#8 Object "furnace", at 0x5570fb94c186, in
#7 Object "furnace", at 0x5570fb94c166, in
#6 Object "furnace", at 0x5570fb899282, in DivDispatchContainer::fillBuf(unsigned long, unsigned long, unsigned long)
#5 Object "furnace", at 0x5570fb88492a, in blip_read_samples
#4 Object "/usr/lib/libc.so.6", at 0x7faba8c36d25, in __assert_fail
#3 Object "/usr/lib/libc.so.6", at 0x7faba8c263db, in
#2 Object "/usr/lib/libc.so.6", at 0x7faba8c264b7, in abort
#1 Object "/usr/lib/libc.so.6", at 0x7faba8c3e667, in raise
#0 Object "/usr/lib/libc.so.6", at 0x7faba8c8e83c, in
Aborted (Signal sent by tkill() 9352 1000)
Przerwane (zrzut pamięci)

Not a heisenbug, 100% replicable, affects at the very least linux, most likely everyone. How did it slip through? fresh master btw

[freq-mod]

Pressing any note = crash, furnace is completely broken now

[freq-mod]

EDIT 2: only JACK works now. SDL and PortAudio do crash

[ElectricKeet]

Win10 x64, SDL, WASAPI:
I find that it stops crashing when audioBufSize is greater than 256.

[tildearrow]

Please test with Git master. I pushed a fix.

[tildearrow]

Do not close until we have enough confirmation.

[tildearrow]

OK - several users confirm fix to be effective.