Fixes mkmimo to play nicer with slow UDFs
Fixes mkmimo to play nicer with slow UDFs

There was a busy waiting bug on OS X when all the sinks got busy and
poll(2) returned too fast.

zifeishan/deepdive,zifeishan/deepdive,zifeishan/deepdive,zifeishan/deepdive,zifeishan/deepdive,HazyResearch/deepdive,sky-xu/deepdive,HazyResearch/deepdive,HazyResearch/deepdive,shahin/deepdive,HazyResearch/deepdive,sky-xu/deepdive,shahin/deepdive