illumos gate

I don't think this is going to work as you expect because strerror does not alter errno. Your code will always return "Unknown [UNIX ]error". It's worth noting that strerror will return "Unknown error" if the errno is not recognised. I felt this was acceptable and that's why the original patch is like it is. I'm happy to see that someone cares enough about this to contribute though.

Thanks,
Andy.

I'm not sure, but man strerror says:

Upon successful completion, strerror() returns a pointer  to
     the  generated  message string. Otherwise, it sets errno and
     returns a pointer to an error message string. It returns the
     string  "Unknown  error"  if  errnum  is  not  a valid error
     number.

Ok. Got it.