var (
	none  = [...]byte{'n', 'o', 'n', 'e', 0}
	slash = [...]byte{'/', 0}

	forceClone3 = false // Used by unit tests only.
)

// Implemented in runtime package.
func runtime_BeforeFork()
func runtime_AfterFork()
func runtime_AfterForkInChild()

// Fork, dup fd onto 0..len(fd), and exec(argv0, argvv, envv) in child.
// If a dup or exec fails, write the errno error to pipe.