The initial diagnostics were errors, too, not warnings.  And yes, they
were related to the SETUP_ARGS(...) macro.  Before I even posted this
issue, I narrowed down the pre-processed code and discovered that in
fact there was an incompatible type being passed by the caller to the
callee.  I too can build this successfully under gcc version 3.3.3, but
that does not help me with building a load file for the targeted
NonStop platform.