0.21.6

Added

• futhark bench now explicitly notes when a tuning file is not
  present.

• futhark bench, futhark test and friends are now better at
  handling fatally terminating programs (e.g. segmentation faults).

• Generated C code is now a lot smaller for large programs, as error
  recovery has been more centralised (#1584).

Fixed

• Some bugs in checking for local memory capacity for particularly
  exotic generated code.

• Insufficient hoisting of allocation sizes led to problems with
  memory expansion in rare cases (#1579).

• Conversion of floating-point NaNs and infinities to integers now
  well defined (produces zero) (#1586).

• Better handling of OOM for certain short-lived CPU-side allocations (#1585).