internal/rosa: lazy initialise all artifacts

This improves performance, though not as drastically as lazy initialising llvm.

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

internal/rosa/kernel.go

@@ -16,7 +16,7 @@ func (t Toolchain) newKernel(
 		checksum = "-V1e1WWl7HuePkmm84sSKF7nLuHfUs494uNMzMqXEyxcNE_PUE0FICL0oGWn44mM"
 	)
 	return t.New("kernel-"+version, slices.Concat([]pkg.Artifact{
-		t.NewMake(),
+		t.Load(Make),
 	}, extra), nil, nil, `
 export LLVM=1
 export HOSTLDFLAGS="${LDFLAGS}"
@@ -30,11 +30,11 @@ chmod -R +w /usr/src/linux && cd /usr/src/linux
 	)))
 }
 
-// NewKernelHeaders returns a [pkg.Artifact] containing kernel headers.
-func (t Toolchain) NewKernelHeaders() pkg.Artifact {
+func (t Toolchain) newKernelHeaders() pkg.Artifact {
 	return t.newKernel(`
 make "-j$(nproc)" \
 	INSTALL_HDR_PATH=/work/system \
 	headers_install
-`, t.NewRsync())
+`, t.Load(Rsync))
 }
+func init() { artifactsF[KernelHeaders] = Toolchain.newKernelHeaders }