Use `vfasl-convert-file` to convert to the vfasl format, something
like this:
(vfasl-convert-file "orig/petite.boot" "new/petite.boot" '())
(vfasl-convert-file "orig/scheme.boot" "new/scheme.boot" '("petite"))
(vfasl-convert-file "orig/racket.boot" "new/racket.boot" '("petite" "scheme"))
original commit: a40886e2fba741ca8cfc5ebd16b902d6414da0ae
