Platform-specific code that determines if a directory is OK to use
as a repository has been taught to report more details, especially
on Windows.
* js/safe-directory-plus:
mingw: handle a file owned by the Administrators group correctly
mingw: be more informative when ownership check fails on FAT32
mingw: provide details about unsafe directories' ownership
setup: prepare for more detailed "dubious ownership" messages
setup: fix some formatting
7fac7b563b