I think the Standard is very wrong.  What is the semantics of the following

   value: INTEGER_64
      external "C inline"
      end

Is it 0?  What if the type is BOOLEAN, CHARACTER_32, etc.  What if the
return type is a user defined expanded type?

In any case, even if this is the semantics (default value of that type)
then you have a bug in the compiler.  Compile attached program and
execute it.  REAL_64, INTEGER_64 and NATURAL_64 values are garbage,
not 0.

Reopening this report.