How do I make `go get` to build against x86_64 instead of i386

I am trying to use either go-qml or gotk3 to build a very simple desktop app that can run under OS X. However when I try to use go get to install either library, it will try to build for i386 and skip the libraries that were build against x86_64. I could try to get the 32 bit version of those libraries, but I would prefer to build for 64bit. How do I instruct go get to do so?

The warnings that are followed by errors look lie this:

go get gopkg.in/qml.v1
# gopkg.in/qml.v1
ld: warning: ld: warning: ld: warning: ignoring file /usr/local/Cellar/qt5/5.3.2/lib/QtWidgets.framework/QtWidgets, file was built for x86_64 which       is not the architecture being linked (i386): /usr/local/Cellar/qt5/5.3.2/lib/QtWidgets.framework/QtWidgetsignoring file /usr/local/Cellar/qt5/5.3.2/lib/QtGui.framework/QtGui, file was built for x86_64 which is not the architecture being linked (i386): /usr/local/Cellar/qt5/5.3.2/lib/QtGui.framework/QtGuiignoring file /usr/local/Cellar/qt5/5.3.2/lib/QtQuick.framework/QtQuick, file was built for x86_64 which is not the architecture being linked (i386): /usr/local/Cellar/qt5/5.3.2/lib/QtQuick.framework/QtQuick

Set the environment variable GOARCH to the value amd64. This instructs the go command to generate files for amd64. Other valid values for GOARCH are 386 and arm.

F.Y.I.

> The Go compilers support the following instruction sets:
>
> - amd64, 386
> - The x86 instruction set, 64- and 32-bit.
> - arm64, arm
> - The ARM instruction set, 64-bit (AArch64) and 32-bit.
> - mips64, mips64le, mips, mipsle
> - The MIPS instruction set, big- and little-endian, 64- and 32-bit.
> - ppc64, ppc64le
> - The 64-bit PowerPC instruction set, big- and little-endian.
> - riscv64
> - The 64-bit RISC-V instruction set.
> - s390x
> - The IBM z/Architecture.
> - wasm
> - WebAssembly.
>
> (from: Introduction | Installing Go from source | Doc @ golang.org)

Also, you can go tool dist list to check the available architectures to build in your machine.

$ go tool dist list
aix/ppc64
android/386
android/amd64
android/arm
android/arm64
darwin/amd64
darwin/arm64
dragonfly/amd64
freebsd/386
(* snip *)
    

To build a static binary for macOS (Intel/ARM64) would be as below. In this manner, I suppose GOOS="darwin" GOARCH="arm64" combination will be for M1 architecture.

MyVar="foo"

CGO_ENABLED=0 \
        GOOS="darwin" \
        GOARCH="amd64" \
        GOARM="" \
        go build \
        -ldflags="-s -w -extldflags \"-static\" -X 'main.myVar=${MyVar}'" \
        -o="/path/to/export/bin/myApp" \
        "/path/to/main.go"

To compile for Linux on ARM v6, such as RaspberryPi Zero W, the combination would be as below.

$ CGO_ENABLED=0 GOOS="linux" GOARCH="arm" GOARM="6" go build .