Stumbled on this when trying to add a program to a version control tree, but disconnect
it from go build ./...

% cat main.go
// +build ignore
package main

import _ "github.com/kr/pty"

func main() {}
% rm -rf $GOPATH/github.com/kr/pty
% rm -rf $GOPATH/pkg
% go get -v
github.com/kr/pty
_/private/tmp/test
% 

I was expecting:

% go get -v
% 

My setup:

% go version
go version go1.0.3
% go env GOOS
darwin
% go env GOARCH
amd64
%