internal/rosa: early toybox variant

This is a variant of toybox with unfinished tools enabled, for artifacts that will end up in a dependency loop without them.

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

internal/rosa/rosa.go

@@ -178,6 +178,8 @@ var absCureScript = fhs.AbsUsrBin.Append(".cure-script")
 const (
 	// TExclusive denotes an exclusive [pkg.Artifact].
 	TExclusive = 1 << iota
+	// TEarly hints for an early variant of [Toybox] to be used when available.
+	TEarly
 )
 
 // New returns a [pkg.Artifact] compiled on this toolchain.
@@ -253,6 +255,10 @@ ln -vs ../usr/bin /work/bin
 
 		boot := t - 1
 		musl, compilerRT, runtimes, clang := boot.NewLLVM()
+		toybox := Toybox
+		if flag&TEarly != 0 {
+			toybox = toyboxEarly
+		}
 		support = slices.Concat(extra, []pkg.Artifact{
 			cureEtc{newIANAEtc()},
 			musl,
@@ -260,7 +266,7 @@ ln -vs ../usr/bin /work/bin
 			runtimes,
 			clang,
 			boot.Load(Mksh),
-			boot.Load(Toybox),
+			boot.Load(toybox),
 		})
 		env = fixupEnviron(env, []string{
 			EnvTriplet + "=" + triplet(),