Defect in XSH gets

[Geoff Clare <yyy@xxxxxxxxxxxxx>]

@ page 568 line 18662 section gets comment [gwc gets OB]

Problem:

In interpretation AI-053 there is a proposed change to mark the
asctime() and ctime() functions as obsolescent in the next
revision, with the rationale "The standards developers decided to
mark the XXXXX() functions as obsolescent even though it is in the C
Standard due to the possibility of buffer overflow."

The same rationale also applies to the gets() function.  It should
therefore be marked obsolescent as well.

Action:

Mark the gets() function obsolescent in the SYNOPSIS on page 568 with
the OB marker and shading.

In the RATIONALE for gets(), change "None" on line 18691 to:

    "The standards developers decided to mark the gets() function
    as obsolescent even though it is in the C Standard due to the
    possibility of buffer overflow."