[patch, fortran] Fix PR 38536

[Thomas Koenig]

Hi Tobias,

> Dear Thomas,
> 
> Thomas Koenig wrote:
>> I applied your patch with the test reversed and tested it with the
>> following source:
>>
>> [...]
>>    interface
>>       subroutine fun(arg) BIND(C)
>>         use iso_c_binding
>>         type(c_ptr) :: arg
> [...]
>> void fun(void *);
> 
> The interface does not really match. On the Fortran side, you have "void
> **" on the C side you only have "void *".

You learn something new every day...

Your patch is OK with the test for gfc_is_simply_contiguous reversed,
regression-testing and an appropriate test case and change to
c_loc_tests_16.f90.

	Thomas