[PATCH] Use C99-compliant scanf under _GNU_SOURCE.

[Joseph Myers]

On Wed, 21 Feb 2018, Zack Weinberg wrote:

> leads me to believe that it was added in POSIX.1-2008, but it's (sort
> of) gated on __USE_XOPEN2K right now, which corresponds to

That's probably on the basis of POSIX.1-2001 implying C99 (so implying C99 
%a semantics).

> POSIX.1-2001, not -2008.  "SD5-XSH-ERN-132 is applied" in the change
> history on the Issue 7 version of the page makes me think it might
> have been added in a minor update to -2001, but then why doesn't it
> show up on the online version of -2001?

Because that was a non-bug-fix enhancement request, so a new feature only 
for the 2008 edition, not the 2004 bug-fix edition (this predates the 
present issue tracking system, wherein you have explicit "issue8" tags to 
indicate more explicitly feature changes that are only intended for the 
next major revision of POSIX).

-- 
Joseph S. Myers
joseph@codesourcery.com