Dear all,

when looking at output item lists we didn't catch procedures
and procedure pointers and ran into a gfc_internal_error().
Such items are not allowed by the Fortran standard, e.g. for
procedure pointers there is

C1233 (R1217) An expression that is an output-item shall not
              have a value that is a procedure pointer.

Attached patch generates an error instead.

Regtested on x86_64-pc-linux-gnu.  OK for mainline?

Thanks,
Harald