crashCatcherInstall hangs if OpenMW is compiled against macOS 10.13 SDK

Base SDK version seems to be the culprit because it'd been working fine until we bumped it. Nope, openmw-44 branch works just fine with 10.13 SDK.

Initial report: https://forum.openmw.org/viewtopic.php?f=20&t=1808&start=330#p56657.

UPD I used git bisect and 467989cdd506bc9718f25d406ebdd3cc82092f77 (!21 (merged)) is the culprit