Reproduced your numbers on Linux, very nice. For higher input params (deeper trees), the difference between `--gc:arc` and `--gc:boehm` shrinks, but arc remains slightly faster.
Not using `-d:release -d:danger` (development build) obviously results in much slower binaries, but gives the same gc ranking as the production build, with one notable exception: boehm is three times as fast as arc then. Is there an obvious reason for this?
