The `arch`/`opsys` testsuite predicates are inconsistent and confusing
When testing cross GHC, arch
actually represents target arch, which is desirable, but opsys
represents host OS! This is inconsistent and confusing, and a lot of existing when(opsys(...), ...)
logic in the testsuite is written without cross compilation in mind.
Should we refactor these predicates to take host
/target
prefixes?