[Bug fortran/96486] get_environment_variable crashes for environment variables that are empty strings

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96486

--- Comment #29 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Mark Eggleston
<markeggleston@gcc.gnu.org>:

https://gcc.gnu.org/g:de09e7ebc9d5555653745a103eef2b20c7f1dd76

commit r11-2819-gde09e7ebc9d5555653745a103eef2b20c7f1dd76
Author: Mark Eggleston <markeggleston@gcc.gnu.org>
Date:   Mon Aug 10 08:07:39 2020 +0100

    Fortran  :  get_environment_variable runtime error PR96486

    Runtime error occurs when the type of the value argument is
    character(0):  "Zero-length string passed as value...".
    The status argument, intent(out), will contain -1 if the value
    of the environment is too large to fit in the value argument, this
    is the case if the type is character(0) so there is no reason to
    produce a runtime error if the value argument is zero length.

    2020-08-24  Mark Eggleston  <markeggleston@gcc.gnu.org>

    libgfortran/

            PR fortran/96486
            * intrinsics/env.c: If value_len is > 0 blank the string.
            Copy the result only if its length is > 0.

    2020-08-24  Mark Eggleston  <markeggleston@gcc.gnu.org>

    gcc/testsuite/

            PR fortran/96486
            * gfortran.dg/pr96486.f90: New test.