use xx-info for multiarch build

Dockerfile.image

@@ -1,7 +1,18 @@
-# syntax=docker/dockerfile:1
+FROM --platform=$BUILDPLATFORM tonistiigi/xx AS xx
+
 FROM --platform=$BUILDPLATFORM golang:alpine AS build
+# copy xx scripts to your build stage
+COPY --from=xx / /
 ARG TARGETPLATFORM
 ARG BUILDPLATFORM
-RUN echo "I am running on $BUILDPLATFORM, building for $TARGETPLATFORM" > /log
+RUN xx-info env
+RUN export GOOS=$(xx-info os) &&\
+    export GOARCH=$(xx-info arch) &&\
+    make vendor &&\
+    scripts/build_flannel.sh &&\
+    mv dist-dist/flannel-${GOARCH} /flannel
+
 FROM alpine
-COPY --from=build /log /log
+ARG GOARCH
+COPY --from=build /flannel /flannel
+