Rationale:
1. This value has already changed since v1.2 (v1.2 MPI_MAX_PORT_NAME
== 36). Hence, this commit simply increases the value from a
previous change.
1. The changes does increase OMPI's memory footprint slightly, but
only when using MPI-2 dynamics. So it is expected that the change
will have minimal impact on the overall footprint.
1. The change is helpful for nodes that have 4 or more IP networks
(e.g., regular ethernet and multiple IP-over-<pick your favorite
high-speed network> networks). Without this change, invoking
MPI_COMM_SPAWN on hosts with 4 or more IP networks will fail
because we'll exceed 256 bytes for the port name. Some OMPI
developer test clusters already have this kind of configuration
(e.g., Cisco); it is expected that this is not too common in the
real world yet, but with "manycore" coming, having multiple
IP-based networks in a single server will likely become more
common.
This commit was SVN r19638.
8de0663ae0