Fix `make test_SPM` by backporting 7adfb3c233fc3fdeacbb3933d7d13b4c2a3a2eed and using the default Swift compiler unless TOOLCHAIN is defined
Fix `make test_SPM` by backporting 7adfb3c233fc3fdeacbb3933d7d13b4c2a3a2eed and using the default Swift compiler unless TOOLCHAIN is defined

groue/GRDB.swift,groue/GRDB.swift,groue/GRDB.swift,groue/GRDB.swift