Re: master 691015fedb: Fix filelock.c for Haiku

[Eli Zaretskii <eliz@gnu.org>]

> diff --git a/src/filelock.c b/src/filelock.c
> index a213c2b3ca..8453f17cd4 100644
> --- a/src/filelock.c
> +++ b/src/filelock.c
> @@ -608,7 +608,7 @@ lock_if_free (lock_info_type *clasher, char *lfname)
>        err = current_lock_owner (clasher, lfname);
>        if (err != 0)
>  	{
> -	  if (err < 0)
> +	  if (err == -1 || err == -2)
>  	    return -2 - err; /* We locked it, or someone else has it.  */
>  	  break; /* current_lock_owner returned strange error.  */
>  	}
> @@ -616,7 +616,14 @@ lock_if_free (lock_info_type *clasher, char *lfname)
>        /* We deleted a stale lock; try again to lock the file.  */
>      }
>  
> +#if !defined HAIKU \
> +  || defined BE_USE_POSITIVE_POSIX_ERRORS
>    return err;
> +#else
> +  /* On Haiku, POSIX error values are negative by default, but this
> +     code's callers assume that any errno value is positive.  */
> +  return -err;
> +#endif
>  }

Is it guaranteed that no errno value on Haiku cam ever be -1 or -2?
Do we perhaps want to add an assertion to that effect?

Btw, what kind of errno values does Haiku use? what do you see in the
errno.h header there? are all the values negative?