env GOARCH=amd64
env GOAMD64=
go env GOAMD64

# Check that the default doesn't match.
# For the purposes of this test, we use v99 which should
# never match any real systems for quite a few years.
! go list -f '{{ range $f := .GoFiles }}{{ $f }}{{ end }}'
! go build

# settable from the environment
env GOAMD64=v99
go list -f '{{ range $f := .GoFiles }}{{ $f }}{{ end }}'
stdout main.go
go build

# settable from the config file
env GOAMD64=
env GOENV=$WORK/env
go env -w GOAMD64=v99
go list -f '{{ range $f := .GoFiles }}{{ $f }}{{ end }}'
stdout main.go
go build

-- go.mod --
module test

-- main.go --
//go:build amd64.v99

package main

func main() {}