That has been the plan for years now, but given that Erik said the next 6.4last 6.2 release still supports natively bootstrapping, most will likely choose that route instead. Last week, @etcwilde listed the build steps he used to natively bootstrap Swift 6.2 on FreeBSD x86_64 last year. Alternately, the few build patches I use to cross-compile the 6.2 stdlib and compiler for Android are available here, along with the build-script command I invoke.
Of course, most of the work is in porting the Swift standard library to a new platform, these build config issues are secondary.