internal/rosa: gen_init_cpio artifact

This works much better than hacking around the toybox cpio implementation.

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

internal/rosa/kernel.go

@@ -123,3 +123,11 @@ cp -av "$3" "$4"
 	)
 }
 func init() { artifactsF[Kernel] = Toolchain.newKernel }
+
+func (t Toolchain) newGenInitCPIO() pkg.Artifact {
+	return t.New("gen_init_cpio-"+kernelVersion, 0, nil, nil, nil, `
+mkdir -p /work/system/bin/
+cc -o /work/system/bin/gen_init_cpio /usr/src/linux/usr/gen_init_cpio.c
+`, pkg.Path(AbsUsrSrc.Append("linux"), false, kernelSource))
+}
+func init() { artifactsF[GenInitCPIO] = Toolchain.newGenInitCPIO }