Remove dead Fortran .m4 code.

This should have been part of r30151/#4057.  Oops.

cmr=v1.7.4:reviewer=dgoodell
As noted by Paul Hargrove, older PGI compilers support ''some'' of
BIND(C), but not ''all'' of it.  So expand our configure checks to
look for multiple different forms of BIND(C):

 * ISO_C_BINDING
 * SUBROUTINE ... BIND(C)
 * TYPE, BIND(C)
 * TYPE(foo), BIND(C, name="bar")

If the compiler supports all of these, then declare that we support
BIND(C), and the rest of the mpi_f08 checks can continue.  If we miss
any one of those, don't bother continuing -- we won't build the
mpi_f08 module.

Also push the results of all of these tests down to ompi_info so that
they can be reported easily (e.g., "Hey, why doesn't my OMPI
installation have the mpi_f08 module?").

cmr=v1.7.4:reviewer=jsquyres:subject=Expand Fortran BIND(C) configure checks
Drop Mac 10.5 support in README