internal/rosa: fix up dependencies

These are no longer provided by the (incomplete) toybox implementations, so they need to be specified explicitly.

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

internal/rosa/libseccomp.go

@@ -12,7 +12,9 @@ func (t Toolchain) newLibseccomp() pkg.Artifact {
 	return t.New("libseccomp-"+version, 0, []pkg.Artifact{
 		t.Load(Make),
 		t.Load(Bash),
+		t.Load(Gawk),
 		t.Load(Coreutils),
+		t.Load(Diffutils),
 		t.Load(Gperf),
 
 		t.Load(KernelHeaders),