lz4 test (and better build)

Dockerfile

@@ -9,7 +9,9 @@ run go test ./...
 run go build -o /go/bin/init -trimpath .
 
 # ------------------------------------------------------------------------
-from alpine:3.18.4
+from alpine:3.18.4 as initrd
+
+run apk add --no-cache xz
 
 workdir /layer
 run wget -O- https://dl-cdn.alpinelinux.org/alpine/v3.18/releases/x86_64/alpine-minirootfs-3.18.4-x86_64.tar.gz |tar zxv
@@ -22,4 +24,9 @@ copy --from=build /go/bin/init .
 # check viability
 run chroot /layer /init hello
 
-entrypoint ["sh","-c","find |cpio -H newc -o |base64"]
+run find |cpio -H newc -o >/initrd
+
+# ------------------------------------------------------------------------
+from alpine:3.18.4
+copy --from=initrd /initrd /
+entrypoint ["base64","/initrd"]