is okay, because cmd/link also processes the cgo_import_static directive and
knows that _cgo_gcc_Cfunc_sin is expected to be supplied by a host
object file, so cmd/link does not treat the missing symbol as an error when
creating go.o. Indeed, the definition for _cgo_gcc_Cfunc_sin will be
provided to the host linker by foo2.cgo.o, which in turn will need the