hairtunes: implement a simple LCG-based RNG for dithering
hairtunes: implement a simple LCG-based RNG for dithering

We are calling out to libc's rand() function, which has significant
overhead, especially since we are calling it 88200 times per second
(2 channels * 44100 samples).

Implement a very simple linear congruential generator in our code that
is plenty good enough for dithering purposes, and small enough for the
compiler to optimize and inline.

IronBeard/shairport,hendrikw82/shairport,narakai/shairport,albertz/shairport,narakai/shairport,bowlofstew/shairport,albertz/shairport,bowlofstew/shairport,skaman/shairport,hendrikw82/shairport,hendrikw82/shairport,narakai/shairport,skaman/shairport,bowlofstew/shairport,IronBeard/shairport,IronBeard/shairport