internal/rosa: register custom artifacts

This also encodes extra information for iana-etc.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/busybox.go

@@ -32,6 +32,16 @@ func (a busyboxBin) Dependencies() []pkg.Artifact {
 	return []pkg.Artifact{a.bin}
 }
 
+func init() {
+	pkg.Register(kindBusyboxBin, func(r *pkg.IRReader) pkg.Artifact {
+		a := busyboxBin{r.Next().(pkg.FileArtifact)}
+		if _, ok := r.Finalise(); ok {
+			panic(pkg.ErrUnexpectedChecksum)
+		}
+		return a
+	})
+}
+
 // String returns the reporting name of the underlying file prefixed with expand.
 func (a busyboxBin) String() string {
 	return "expand-" + a.bin.(fmt.Stringer).String()