Fix the root directory when building for Linux on Windows. (#1609)
Fix the root directory when building for Linux on Windows. (#1609)

Otherwise, the .tar file gets a weird structure that is not well interpreted in Linux; e.g. files get names like ".\a\b\c\file" (that is a filename, not a path).

Co-authored-by: Suvanjan Mukherjee <ab85559404ee8a9104e1577556f6f73d330123a9@google.com>
bazelbuild/rules_docker,bazelbuild/rules_docker,bazelbuild/rules_docker,bazelbuild/rules_docker