dockerfile: use xx in dnsname stage

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

Author: crazy-max

Dockerfile

@@ -67,15 +67,6 @@ RUN --mount=from=runc-src,src=/usr/src/runc,target=. --mount=target=/root/.cache
   CGO_ENABLED=1 xx-go build -mod=vendor -ldflags '-extldflags -static' -tags 'apparmor seccomp netgo cgo static_build osusergo' -o /usr/bin/runc ./ && \
   xx-verify --static /usr/bin/runc
 
-# dnsname CNI plugin for testing
-FROM gobuild-base AS dnsname
-ARG DNSNAME_VERSION
-WORKDIR /go/dnsname
-RUN git clone https://github.com/containers/dnsname.git . \
-  && git checkout -q "$DNSNAME_VERSION"
-RUN --mount=target=/root/.cache,type=cache \
-  set -e; make binaries; mv bin/dnsname /usr/bin/dnsname
-
 FROM gobuild-base AS buildkit-base
 WORKDIR /src
 ENV GOFLAGS=-mod=vendor
@@ -225,6 +216,22 @@ FROM binaries AS buildkit-windows
 # this is not in binaries-windows because it is not intended for release yet, just CI
 COPY --link --from=buildkitd /usr/bin/buildkitd /buildkitd.exe
 
+# dnsname source
+FROM git AS dnsname-src
+ARG DNSNAME_VERSION
+WORKDIR /usr/src
+RUN git clone https://github.com/containers/dnsname.git dnsname \
+  && cd dnsname && git checkout -q "$DNSNAME_VERSION"
+
+# build dnsname CNI plugin for testing
+FROM gobuild-base AS dnsname
+WORKDIR /go/src/github.com/containers/dnsname
+ARG TARGETPLATFORM
+RUN --mount=from=dnsname-src,src=/usr/src/dnsname,target=.,rw \
+    --mount=target=/root/.cache,type=cache \
+    CGO_ENABLED=0 xx-go build -o /usr/bin/dnsname ./plugins/meta/dnsname && \
+    xx-verify --static /usr/bin/dnsname
+
 FROM --platform=$BUILDPLATFORM alpine:${ALPINE_VERSION} AS cni-plugins
 RUN apk add --no-cache curl
 ARG CNI_VERSION