os/user package can not cross compile.

os/user package need cgo support, buf if enable cgo, we can not cross compile.
So, i use "github.com/mitchellh/go-homedir", replace the os/user package
in file spawn_process.go, function SetBaseDirectory(dir string) error {...}
Thanks.

[miketheprogrammer]

Please create a pull request

[miketheprogrammer]

We need to replace os/user with go-homedir