This commit adds implementations of gather and igather using
Portals4 triggered operations. The default algorithm is linear,
but binomial can be selected using an MCA parameter -
coll_portals4_use_binomial_gather_algorithm.
pkg{data,lib,includedir}, use our own ompi{data,lib,includedir}, which is
always set to {datadir,libdir,includedir}/openmpi. This will keep us from
having help files in prefix/share/open-rte when building without Open MPI,
but in prefix/share/openmpi when building with Open MPI.
This commit was SVN r30140.
