Swift compiler error with xcode12.2

I compiler swift in macOS 10.15.4 , Xcode 12.2, swift version swift-5.3.1-RELEASE

build-script --release-debuginfo --debug-swift --Xcode

but I found this error:

but none of these is a common dependency of the other(s). This is not
allowed by the Xcode "new build system".

how can I change "build system" whith the build commond string?