RFC: Change to sys_errlist

[Terry Lambert]

Matthew Emmerton wrote:
> This is a RFC on a change to sys_errlist for errno = 0.
> 
> On Linux, if perror() or strerror() is called with errno = 0, the resulting
> string is "Success".
> On FreeBSD, the resulting string is "Unknown error: 0".
> 
> I think that FreeBSD's output is unintentionally confusing, as errno = 0
> implies success.
> 
> The following patch will change the output to the Linux behaviour.
> 
> I appreciate any comments.

Actually, I ran into a situation on MacOS X the other day that had
a system call with a -1 return code with an errno == 0.

I would personally like to distinguish this case, if only for the
purpose of catching kernel errors.  Saying "Success" when in fact
the system call is returning -1 is a bogus thing to do.

-- Terry