[patch] Fix for heap overflow in wscanf (BZ 16618)

[Paul Eggert]

Carlos O'Donell wrote:
> I'd read the POSIX wording differently.

Although Rich's interpretation is correct for current POSIX, thanks to Eric 
Blake the next release of POSIX (Issue 8) is planned to change this, and to 
require 'free' to leave errno alone, which as I understand it is your preferred 
interpretation.  Please see:

http://austingroupbugs.net/view.php?id=385

Because of this, glibc 'free' should not set errno if the user invokes 'free' in 
a conforming way.  Setting errno will be a conformance bug once Issue 8 comes 
out, and glibc should be fixed to conform well before that.  Also, the glibc 
documentation should be changed to discuss this issue.  I have filed a glibc bug 
report to that effect, here:

https://sourceware.org/bugzilla/show_bug.cgi?id=17924