Dear all,

the attached simple patch fixes a (9+) regression for passing
to a CONTIGUOUS,TARGET dummy an *effective argument* that is
contiguous, although the actual argument is not simply-contiguous
(it is a pointer without the CONTIGOUS attribute in the PR).

Since a previous attempt for a patch lead to regressions in
gfortran.dg/bind-c-contiguous-3.f90, which is rather dense,
I decided to enhance the current testcase with various
combinations of actual and dummy arguments that allow to
study whether a _gfortran_internal_pack is generated in
places where we want to.  (_gfortran_internal_pack does not
create a temporary when no packing is needed).

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

I would like to backport this - after a grace period - to
at least 13-branch.  Any objections here?

Thanks,
Harald