message: Don't check patch command on Windows
diff: @@ -99,7 +99,8 @@ def _execute_and_check_ret_code(repo_ctx, cmd_and_args):
  # Apply a patch_file to the repository root directory
  # Runs 'patch -p1'
  def _apply_patch(repo_ctx, patch_file):
  - if not repo_ctx.which("patch"):
  + # Don't check patch on Windows, because patch is only available under bash.
  + if not _is_windows(repo_ctx) and not repo_ctx.which("patch"):
  fail("patch command is not found, please install it")
  cmd = [
  