Declare cuserid in unistd.h for UNIX98 and before (bug 20043)

[Zack Weinberg]

On Wed, May 4, 2016 at 11:48 AM, Joseph Myers <joseph@codesourcery.com> wrote:
>
> -/* The Single Unix specification demands this prototype to be here.
> -   It is also found in <stdio.h>.  */
> +/* The Single Unix specification demands these prototype to be here.
> +   They are also found in <stdio.h>.  */

Since you're touching this comment anyway, would you mind fixing the
grammar and clarifying which version(s) of SUS are meant? I would
suggest something along the lines of

/* Prior to Issue 6, the Single Unix specification required these prototypes
   to appear in this header.  They are also found in <stdio.h>.  */

only with the correct version information.

zw