使用Golang 1.10无法编译Windows DLL

I'm having issues building a Windows DLL in Golang 1.10, which is supported in this latest version:

"The various build modes have been ported to more systems. Specifically, c-shared now works on linux/ppc64le, windows/386, and windows/amd64;" (Source: https://golang.org/doc/go1.10)

I have a very simple program right now (main.go) that only exports one function "Test", but am having issues when using the following "go build" command: env GOOS=windows GOARCH=386 go build -buildmode=c-shared main.go

Specifically, receiving the can't load package: package main: build constraints exclude all Go files in [PATH] error. The source code for main.go is shown below:

package main

import (
    "C"
    "fmt"
)

func main() {
    fmt.Println("from main")
}

//export Test
func Test() string {
    return "this is a test"
}

I've never encountered this error before and building without specifying GOOS and GOARCH works. Hoping someone has encountered this issue and can help me out.

  1. Make sure you have MinGW installed on Ubuntu: sudo apt-get install gcc-mingw-w64-i686 and sudo apt-get install gcc-mingw-w64-x86-64

  2. Compile using the following commands: env GOOS=windows GOARCH=386 CGO_ENABLED=1 CC=i686-w64-mingw32-gcc go build -buildmode=c-shared -o main.dll main.go and env GOOS=windows GOARCH=amd64 CGO_ENABLED=1 CC=x86_64-w64-mingw32-gcc go build -buildmode=c-shared -o main.dll main.go

  3. Verify generated DLL works by testing the "Test" export: rundll32.exe main.dll,Test