Building Windows version fails

[CaptainFlint]

When I try to build Windows version on a Linux machine, it ends up like this:

docker run --rm -i --privileged  -e DOCKER_CROSSPLATFORMS -e BUILD_APT_MIRROR -e BUILDFLAGS -e KEEPBUNDLE -e DOCKER_BUILD_ARGS -e DOCKER_BUILD_GOGC -e DOCKER_BUILD_OPTS -e DOCKER_BUILD_PKGS -e DOCKER_BUILDKIT -e DOCKER_BASH_COMPLETION_PATH -e DOCKER_CLI_PATH -e DOCKER_DEBUG -e DOCKER_EXPERIMENTAL -e DOCKER_GITCOMMIT -e DOCKER_GRAPHDRIVER -e DOCKER_LDFLAGS -e DOCKER_PORT -e DOCKER_REMAP_ROOT -e DOCKER_STORAGE_OPTS -e DOCKER_TEST_HOST -e DOCKER_USERLANDPROXY -e DOCKERD_ARGS -e TEST_INTEGRATION_DIR -e TEST_SKIP_INTEGRATION -e TEST_SKIP_INTEGRATION_CLI -e TESTDEBUG -e TESTDIRS -e TESTFLAGS -e TESTFLAGS_INTEGRATION -e TESTFLAGS_INTEGRATION_CLI -e TEST_FILTER -e TIMEOUT -e VALIDATE_REPO -e VALIDATE_BRANCH -e VALIDATE_ORIGIN_BRANCH -e HTTP_PROXY -e HTTPS_PROXY -e NO_PROXY -e http_proxy -e https_proxy -e no_proxy -e VERSION -e PLATFORM -e DEFAULT_PRODUCT_LICENSE -e PRODUCT -v "/root/moby/bundles:/go/src/github.com/docker/docker/bundles" -v "/root/moby/.git:/go/src/github.com/docker/docker/.git" -v docker-dev-cache:/root/.cache    "docker-dev:vz7u15" DOCKER_CROSSPLATFORMS=windows/amd64 hack/make.sh cross
hack/dind: 29: exec: DOCKER_CROSSPLATFORMS=windows/amd64: not found
make: *** [win] Error 127

I edited the Makefile by moving the variable devinition in front of the command:

 win: build ## cross build the binary for windows
-       $(DOCKER_RUN_DOCKER) DOCKER_CROSSPLATFORMS=windows/amd64 hack/make.sh cross
+       DOCKER_CROSSPLATFORMS=windows/amd64 $(DOCKER_RUN_DOCKER) hack/make.sh cross

This way it worked fine. Also, in the "run" target I can see a different approach, with explicit call of the shell executable. It could be used here as well:

$(DOCKER_RUN_DOCKER) sh -c "DOCKER_CROSSPLATFORMS=windows/amd64 hack/make.sh cross"

[sryze]

I ran into the same problem, fixed it by adding env in front of the var:

$(DOCKER_RUN_DOCKER) env DOCKER_CROSSPLATFORMS=windows/amd64 hack/make.sh cross

But after the build is finished, I can't find the resulting binaries... are they supposed to be under bundles/? because it's empty for me

[CaptainFlint]

For me it's under bundles/cross/windows/amd64, two files: containerutility.exe and dockerd-SUFFIX.exe.

[rgl]

I was also having trouble building this at https://github.com/rgl/docker-ce-windows-binaries-vagrant/actions; but with #41590 it builds fine.

Isn't #41590 OK be merged?