Fix darwin flag when cross-compiling from Linux to MacOS
#909
| Job | Run time |
|---|---|
| 6m 17s | |
| 5m 48s | |
| 7m 13s | |
| 6m 29s | |
| 10m 17s | |
| 12m 25s | |
| 12m 16s | |
| 12m 12s | |
| 4s | |
| 18m 25s | |
| 33m 22s | |
| 2h 4m 48s |