I'd suggest you might be better making you fpc.cfg work with all your versions of FPC.
The one supplied with fpc322 is not up to it but one with 324rc1 makes much better use of replaceable parameters. And you can have different sections depending on what you are compiling.
But if you still want to change things, you can use -n to stop if reading the default and @ to get to to read the one you do want.
Davo
edit - Hmm, I should have spotted "..using make..." !