compiler: disable self-hosted x86_64 backend on OpenBSD

Same as 97ecb6c551eb628e5a37d18d5a9720d3714a04ef for NetBSD.
a9773944dcAlex Rønne Petersen committed on 7/30/2025, 3:17:22 PMparent6ec275e
1 file changedLine totals unavailable