[23.0 backport] scripts/build/plugins: don't override CGO_ENABLED set by .variables

[thaJeztah]

• backport https://github.com/docker/cli/pull/5393

The .variables sets CGO_ENABLED=1 on arm; https://github.com/docker/cli/blob/b0c41b78d8c80c5f8faa736cf3c74dc31092e443/scripts/build/.variables#L57-L68 And if enabled, it sets -buildmode=pie; https://github.com/docker/cli/blob/b0c41b78d8c80c5f8faa736cf3c74dc31092e443/scripts/build/.variables#L79-L88

But that looks to be conflicting with the hardcoded CGO_ENABLED=0 in this script, which causes the build to fail on go1.22;

> [build-plugins 1/1] RUN --mount=ro --mount=type=cache,target=/root/.cache     xx-go --wrap &&     TARGET=/out ./scripts/build/plugins e2e/cli-plugins/plugins/*:
0.127 Building static docker-helloworld
0.127 + CGO_ENABLED=0
0.127 + GO111MODULE=auto
0.127 + go build -o /out/plugins-linux-arm/docker-helloworld -tags ' osusergo' -ldflags ' -X "github.com/docker/cli/cli/version.GitCommit=5c123b1" -X "github.com/docker/cli/cli/version.BuildTime=2024-09-02T13:52:17Z" -X "github.com/docker/cli/cli/version.Version=pr-5387" -extldflags -static' -buildmode=pie github.com/docker/cli/cli-plugins/examples/helloworld
0.135 -buildmode=pie requires external (cgo) linking, but cgo is not enabled

This patch sets the CGO_ENABLED variable before sourcing .variables, so that other variables which are conditionally set are handled correctly.

Before this PR:

#18 [build-plugins 1/1] RUN --mount=ro --mount=type=cache,target=/root/.cache     xx-go --wrap &&     TARGET=/out ./scripts/build/plugins e2e/cli-plugins/plugins/*
#18 0.123 Building static docker-helloworld
#18 0.124 + CGO_ENABLED=0
#18 0.124 + GO111MODULE=auto
#18 0.124 + go build -o /out/plugins-linux-arm/docker-helloworld -tags ' osusergo' -ldflags ' -X "github.com/docker/cli/cli/version.GitCommit=c8c402e" -X "github.com/docker/cli/cli/version.BuildTime=2024-09-03T08:28:25Z" -X "github.com/docker/cli/cli/version.Version=pr-5381" -extldflags -static' -buildmode=pie github.com/docker/cli/cli-plugins/examples/helloworld
....

With this PR:

#18 [build-plugins 1/1] RUN --mount=ro --mount=type=cache,target=/root/.cache     xx-go --wrap &&     TARGET=/out ./scripts/build/plugins e2e/cli-plugins/plugins/*
#18 0.110 Building static docker-helloworld
#18 0.110 + GO111MODULE=auto
#18 0.110 + go build -o /out/plugins-linux-arm/docker-helloworld -tags '' -ldflags ' -X "github.com/docker/cli/cli/version.GitCommit=050d9d6" -X "github.com/docker/cli/cli/version.BuildTime=2024-09-03T09:19:05Z" -X "github.com/docker/cli/cli/version.Version=pr-5387"' github.com/docker/cli/cli-plugins/examples/helloworld
....

(cherry picked from commit 9e29967960d97303222e9009e0401008febdfb20)

[thaJeztah]

Not sure what this failure is; perhaps github actions need to be updated in this branch?

Run codecov/codecov-action@v3
  with:
    file: /tmp/coverage.txt
    working-directory: /Users/runner/work/cli/cli/src/github.com/docker/cli
  env:
    GOPATH: /Users/runner/work/cli/cli
    GOBIN: /Users/runner/work/cli/cli/bin
    GO111MODULE: auto
==> macos OS detected
https://uploader.codecov.io/latest/macos/codecov.SHA256SUM
==> SHASUM file signed by key id 806bb28aed779869
==> Uploader SHASUM verified (75086ee436f6f74c4e8f65448eaa399e38bc93bb27a53d057b24b275b9f78c89  codecov)
==> Running version latest
==> Running version v0.8.0
/Users/runner/work/_actions/codecov/codecov-action/v3/dist/codecov -n  -Q github-action-3.1.6 -f /tmp/coverage.txt -C 5fe96b1f63453b6932cc7a659b6799733c422021
Error: spawn Unknown system error -86
    at ChildProcess.spawn (node:internal/child_process:421:11)
    at Object.spawn (node:child_process:761:9)
    at ToolRunner.<anonymous> (/Users/runner/work/_actions/codecov/codecov-action/v3/webpack:/codecov-action/node_modules/@actions/exec/lib/toolrunner.js:413:1)
    at Generator.next (<anonymous>)
    at fulfilled (/Users/runner/work/_actions/codecov/codecov-action/v3/webpack:/codecov-action/node_modules/@actions/exec/lib/toolrunner.js:24:1)

[corhere]

@thaJeztah the latest codecov uploader for macOS is built for arm64, which fails with -EBADARCH on Intel macs. Migrating to the v4 action might work as it uses the codecov cli instead of the uploader. Or simply pin to a release of the uploader that was built for Intel macs

[thaJeztah]

this was already backported through https://github.com/docker/cli/pull/5400