Suppress statement not reached warnings under Solaris Studio

Suppress statement not reached warnings under Solaris Studio

Solaris Studio issues warnings for statements which can not be reached,
such as statements following an infinite loop.  For example, the return
statement will generate a 'statement not reached' warning in the
following code:

    while (1) {
       /*  no breaks or gotos in this body */
    }
    return 0;

Suppress these warnings by conditionally removing such statements when
building under Solaris Studio.

Reviewed-on: https://gerrit.openafs.org/12958
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit f47cb2d4a957910c3e7d4b755f41ddef5dd103c5)

Change-Id: I3ac84edbc18d7b6aebd568e9a1c4a3e47aba5512
Reviewed-on: https://gerrit.openafs.org/13107
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>