gexec/build.go
func BuildIn(gopath string, packagePath string, args ...string) (compiledPath string, err error) {
	return doBuild(gopath, packagePath, nil, args...)
}
func BuildIn(gopath string, packagePath string, args ...string) (compiledPath string, err error) {
	return doBuild(gopath, packagePath, nil, args...)
}
/*
BuildIn is identical to Build but allows you to specify a custom $GOPATH (the first argument).
*/