No polyfill for tar on builds of Windows without native support

[istinecray]

Running relative-deps as is gives me this error (on Windows OS build 14393):

<ref *1> Error: spawnSync tar ENOENT
    at Object.spawnSync (internal/child_process.js:1067:20)
    at spawnSync (child_process.js:602:24)
    at Object.execFileSync (child_process.js:629:15) ...
    at processTicksAndRejections (internal/process/task_queues.js:93:5) {
  errno: -4058,
  code: 'ENOENT',
  syscall: 'spawnSync tar',
  path: 'tar',
  spawnargs: [
    'zxf',
    '..\\PROJECT\\BUILD.tgz',
    '--strip-components=1',
    '-C',
    'node_modules\\@NAMESPACE\\PACKAGE',
    'package'
  ],
  error: [Circular *1],
  status: null,
  signal: null,
  output: null,
  pid: 0,
  stdout: null,
  stderr: null
}

PR here