[Patch, Fortran] PR57530 - fix rejects valid with gfc_type_compatible

[Tobias Burnus]

I accidentally attached a slightly out-dated patch. The old patch 
permitted CLASS<->TYPE differences in cases where the characteristic had 
to match (e.g. dummy arguments in a proc-pointer assignment). - Sorry 
for the confusion.

Build and regtested on x86-64-gnu-linux.
OK for the trunk?

Tobias

Tobias Burnus wrote:
> A TYPE is type compatible with a CLASS if both have the same declared 
> type.
>
> Or in words of the standard (cf. PR):
> "A nonpolymorphic entity is type compatible only with entities of the 
> same declared type. A polymorphic entity that is not an unlimited 
> polymorphic entity is type compatible with entities of the same 
> declared type or any of its extensions." (F2008, 4.3.1.3).
>
> Build and regtested on x86-64-gnu-linux.
> OK for the trunk?