[patch, fortran] Fix PR 89174, segfault on allocate with MOLD

[Paul Richard Thomas]

Hi Thomas,

> Of course, there could also be a more profound way of fixing this
> bug :-)

I wish that it were the case. I am unable to decide whether the design
choices made for an F95 compiler have cause the add-ons to be
intrinsically complicated or whether or whether F2018, extensions and
legacy support is the cause of the complexity - probably both.  Either
way, profundity is rarely to be found in bugfixes.

>
> Regression-tested on x86_64-pc-linux-gnu.  OK for trunk and gcc-8?

Yes, that's good for both branches. Thanks for the fix.

Paul