[patch, fortran] Fix PR 30235

[Brooks Moses]

Brooks Moses wrote:
> Tested on i686_pc_linux_gnu; everything works, except that without the 
> interface.c patch the failures on the new test don't seem to cycle 
> through the -O1, O2, etc. flags like they should; instead I only get this:
> 
>    FAIL: gfortran.dg/altreturn_2.f90  -O  (internal compiler error)
>    FAIL: gfortran.dg/altreturn_2.f90  -O   (test for errors, line 3)
>    FAIL: gfortran.dg/altreturn_2.f90  -O  (test for excess errors)
> 
> Any idea what I'm missing?

Update: All the gfortran-dg "dg-do compile" tests seem to be doing this, 
so I don't think this is a problem with my patch, but with the testsuite.

- Brooks