internal/rosa: diffutils artifact

LLVM tests are not happy with busybox diff.

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

internal/rosa/llvm.go

@@ -127,6 +127,8 @@ func (t Toolchain) newLLVM(variant string, attr *llvmAttr) pkg.Artifact {
 	extra := []pkg.Artifact{
 		t.NewLibffi(),
 		t.NewPython(),
+		t.NewPerl(),
+		t.NewDiffutils(),
 		t.NewKernelHeaders(),
 	}
 	if t == toolchainStage3 {