tcgetwinsize() and tcsetwinsize()

[Florian Weimer]

* Soumendra Ganguly via Libc-help:

> https://www.austingroupbugs.net/view.php?id=1151#c3856, tcgetwinsize()
> and tcsetwinsize() for getting/setting tty winsize are going to appear
> in POSIX.1 issue 8. NetBSD already has them:
>
> 1. http://cvsweb.netbsd.org/bsdweb.cgi/src/lib/libc/termios/tcgetwinsize.c?only_with_tag=MAIN
> 2. http://cvsweb.netbsd.org/bsdweb.cgi/src/lib/libc/termios/tcsetwinsize.c?only_with_tag=MAIN
>
> Also, musl-libc has them. Would implementations of these functions
> using ioctl()+TIOCGWINSZ?TIOCSWINSZ be welcome?

An addition would seem reasonable.  The proposed POSIX change appears
to be compatible with what we have today.

Please note that glibc patches of this size will need copyright
assignment:

  <https://sourceware.org/glibc/wiki/Contribution%20checklist#FSF_copyright_assignment>

If your contribution is potentially covered by your university, the
FSF will likely ask for a copyright disclaimer or assignment from them
as well.

Unfortunately, I have no view into the FSF copyright assignment
process, but I will be able to help you to get your patch ready for
integration into glibc.