[gcc r13-2740] fortran: add link to ISO_VARYING_STRING module [PR106636]

[Martin Liska]

https://gcc.gnu.org/g:d812e8cb2a920fd75768e16ca8ded59ad93c172f

commit r13-2740-gd812e8cb2a920fd75768e16ca8ded59ad93c172f
Author: Martin Liska <mliska@suse.cz>
Date:   Tue Sep 20 14:23:29 2022 +0200

    fortran: add link to ISO_VARYING_STRING module [PR106636]
    
            PR fortran/106636
    
    gcc/fortran/ChangeLog:
    
            * gfortran.texi: Add back link to ISO_VARYING_STRING.

Diff:
---
 gcc/fortran/gfortran.texi | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gcc/fortran/gfortran.texi b/gcc/fortran/gfortran.texi
index fb4a48911ac..4b4ecd528a7 100644
--- a/gcc/fortran/gfortran.texi
+++ b/gcc/fortran/gfortran.texi
@@ -455,7 +455,8 @@ version 2.6, @uref{https://www.openacc.org/}).  See
 The Fortran 95 standard specifies in Part 2 (ISO/IEC 1539-2:2000)
 varying length character strings.  While GNU Fortran currently does not
 support such strings directly, there exist two Fortran implementations
-for them, which work with GNU Fortran.
+for them, which work with GNU Fortran. One can be found at
+@uref{http://user.astro.wisc.edu/~townsend/static.php?ref=iso-varying-string}.
 
 Deferred-length character strings of Fortran 2003 supports part of
 the features of @code{ISO_VARYING_STRING} and should be considered as