[Patch, Fortran] PR54339 - Update gfortran.texi's standard refs, status and TS29113 sections

[Tobias Burnus]

Dominique,

Dominique Dhumieres:
> AFAICT, the links in
>   (version 3.1, @url{http://openmp.org/@/wp/@/openmp-specifications/}).
>   @uref{http://www.fortran.com/@/iso_varying_string.f95} and at
>   @uref{ftp://ftp.nag.co.uk/@/sc22wg5/@/ISO_VARYING_STRING/}.
> are all broken.

Might be in the PDF version (untested), but they do work in the HTML 
version at http://gcc.gnu.org/onlinedocs/gfortran/Standards.html

Tobias