code: func (e *Env) SetEntry(entry string) {
  	if e.env == nil {
  		e.env = make(map[string]string)
  	}
  
  	// "entry" must be a well-formed "key=value" entry. If it doesn't have an "=",
  	// we will forcibly add one to make it well-formed.
  	if strings.IndexRune(entry, '=') < 0 {
  		entry += "="
  	}
  	k, _ := Split(entry)
  	if len(k) > 0 {
  		e.env[e.normalizeKey(k)] = entry
  	}
  }
docs: // SetEntry sets the supplied environment to a "KEY[=VALUE]" entry.