There are a few changes:
* Callers can specify if they want recursive behaviour or not
* All file listings to tar are sent on stdin, to handle long lists better
* We can pass in a list of filenames which will be created as empty
files in the tarball
This is exactly what we want for the creation of layer tarballs given
a container fs, a set of files to add and a set of whiteout files to create.
Upstream-commit: 223280f31967edb7b3eb325cce8a3b82939c0f2b
Component: engine
ce8763b123