To cover the case when multiple communicators are created by
MPI_Comm_idup.

Signed-off-by: Pavan Balaji <balaji@mcs.anl.gov>

Reviewed by buntinas.

Reviewed by buntinas.

Reviewed by dinan.

From MPI Forum ticket 168:
http://svn.mpi-forum.org/trac2/mpi-forum-web/ticket/168

This version will not work for multithreaded initializations of MPI.
Unfortunately, an implementation that deals with multithreading
correctly is much more complex.

Includes a simple test of the MPIX_Comm_idup functionality.

No reviewer.

Thanks to N. Radclif @ Cray for the bug report, proposed fix, and
regression test case.  Note that the fix in this commit is more complete
than the one originally proposed in that ticket.

No reviewer.

strict-mpi is enabled. Fixes tt#1549.

functions are integrated into the MPICH2 library build and do not
require a separate build.

Reviewed by buntinas.

MPICH2 currently fails this test when MPICH_COMM_SPLIT_USE_QSORT=false
is set (the current bubble sort impl is unstable).  See also tt#1493.

Reviewed by buntinas@.

significant additional functionality.  This change contains the infrastructure
for SMP collectives and an implementation of SMP-aware broadcast.

Reviewed by thakur@.