a compilation or link failure (implied by what you say above). Please show us how the current code fails on s390 and adjust your log message to start with something like this: build/fdasd: avoid compilation failure on s390 Also, this part looks like it won't always work: - arch/$(OS).c + arch/$(OS).c \ + arch/$(OS).h since there is no .h file when $(OS) is "gnu" or "beos".