ref: cad03a966cd487cf0b9bb24cb02b971337282911 dir: /lib/thread/ncpu+plan9.myr/
use std pkg thread = const ncpu : (-> int) ;; const ncpu = { match std.intparse(std.getenvv("NPROC", "")) | `std.Some n: -> n | `std.None: -> 1 ;; }