[Q] pragma Warnings

[Georg Bauhaus <rm.tsoh+bauhaus@maps.futureapps.de>]

In http://www.adacore.com/2007/11/19/ada-gem-18/
Bob Duff explains how to use GNAT's pragma Warnings.

The effect is that GNAT users can control individual
warnings by placing suitably crafted pragmas in
source code, next to the lines that trigger the warning.

Another effect is that some Ada programs are used with
two or more targets and are translated using two or more
different compilers. In this case, the non-GNAT compiler
might complain about a non-supported pragma Warnings.
Placing the pragmas in the source will then defeat
the pragma's purpose because the compiler will issue
a warning about an unknown Warnings pragma. (Hopefully,
the other compiler will not report an error message,
as is predictably the case with link library pragmas.)

Is there an alternative to placing compiler specific
pragma Warnings in portable (pragma-wise) Ada programs?

(E.g., using the pragma as a configuration pragma,
in a connected region of source code but not right in it?
Using a smart IDE's filtering capabilities?)