ref: 84393ead97a2e189b6057420ad7d94170b9aa00f dir: /lib/thread/ncpu+plan9.myr/
use std pkg thread = const ncpu : (-> int) ;; const ncpu = { match std.intparse(std.getenvv("NPROC", "1")) | `std.Some n: -> n | `std.None: -> 1 ;; }