3.2 PATCH: Fully support parallel gnat1/gnatbind builds

[Florian Weimer]

Joe Buck <Joe.Buck@synopsys.com> writes:

> The usual way to handle such things is with configure-time tests: does
> the existing Ada compiler support pragma Unreferenced?

Correct.

> If so, use it, otherwise use pragma Warnings.

This requires source code preprocessing, which is not a terribly good
idea.

Note that pragma Warnings is unnecessary if suitable command line
options are given, but there doesn't seem to be a way to force an
older GNAT version not to generate warnings for unrecognized pragmas
(which turn into errors in -gnatg mode).