Version
#if MIN_VERSION_process(1,2,0)
#if MIN_VERSION_base(4,7,0)
Host os
#if defined(darwin_HOST_OS)
#if defined(linux_HOST_OS)
format
#if X
#elif Y
#else
#endif
Version
#if MIN_VERSION_process(1,2,0)
#if MIN_VERSION_base(4,7,0)
Host os
#if defined(darwin_HOST_OS)
#if defined(linux_HOST_OS)
format
#if X
#elif Y
#else
#endif