v.builder: fix cross compiling from linux to windows with -os windows -subsystem windows
#7270
| Job | Run time |
|---|---|
| 59m 4s | |
| 1h 34m 20s | |
| 2h 4m 51s | |
| 2h 29m 54s | |
| 4m 6s | |
| 3h 17m 7s | |
| 10h 29m 22s |