Tested in poudriere:
| rel-arch | devel/rubygem-listen |
|------------|----------------------|
| 9.3-i386 | OK |
| 9.3-amd64 | OK |
| 10.3-i386 | OK |
| 10.3-amd64 | OK |
| 11.0-i386 | OK |
| 11.0-amd64 | OK |
The host system:
FreeBSD AprilRyan.norad 11.0-STABLE FreeBSD 11.0-STABLE #0 r310323