Update to 1.224

Upstream changes:
1.224    2019-03-02
  - No changes since 1.223

1.223    2019-02-14 (TRIAL)
  - Use File::Spec to get tmpdir instead of hardcoding (thanks, Desmond
  Daignault)

1.222    2018-04-29 (TRIAL)
  - Properly quote C strings passed in DEFINE (thanks, Salvador Fadi単o)
  - Fix memory leak by decreasing reference count (thanks, Daniel Spang)

(wen)