proposal: go install -o (support specifying the path name/directory more directly) - multi arch CI concern

[ldemailly]

In order to take advantage of the new BuildInfo it's ideal (imo) to replace the before classic best practice:
go build with -ldflags -X main.version=1.2.3 by go install pkg@v1.2.3

But go install doesn't simply let you specify where to install the binary. It puts it in GOPATH/bin when on the native architecture and GOPATH/bin/$arch/ when not; which makes it hacky and hard to just produce the binaries in a multi arch CIs

Example: before:

CGO_ENABLED=0 GOOS=windows go build -a -ldflags \
'-s -X fortio.org/fortio/version.version=1.28.0 -X "fortio.org/fortio/version.buildInfo=2022-04-26 00:40 57e9d8f01c342a4c1b5d96f883f81128b04d991a"' \
 -o /tmp/fortio.exe fortio.org/fortio

after/now

GOPATH=/build CGO_ENABLED=0 GOOS=darwin /usr/local/go/bin/go install -a -ldflags -s fortio.org/fortio@v1.29.0-pre16
mv -f /build/bin/*_*/fortio* /build/bin
rmdir /build/bin/*_*

I end up having to use GOPATH to try to set where the binary ends up as well as using some hacks to deal with native vs non native arch

Let me know what you think

[seankhliao]

Duplicate of #44469

[ldemailly]

Thanks ! sorry for the dup! hopefully this multi arch build context helps for the other one too