message: Fix incorrect OS masking
  Summary: Need to actually `#ifdef` the content of a "public" method. Follow-up for {D24660475 (https://github.com/facebook/redex/commit/0b81ca45429f901b7d3c243b055222b0864789f1)}.
diff: @@ -588,7 +588,11 @@ class AfterPassSizes {
  #endif
  }
  - void wait() { check_open_jobs(/*no_hang=*/false); }
  + void wait() {
  +#ifdef __linux__
  + check_open_jobs(/*no_hang=*/false);
  +#endif
  + }
  private:
  #ifdef __linux__
  