Merge branch 'mt/dir-iterator-updates'

Adjust the dir-iterator API and apply it to the local clone
optimization codepath.

* mt/dir-iterator-updates:
  clone: replace strcmp by fspathcmp
  clone: use dir-iterator to avoid explicit dir traversal
  clone: extract function from copy_or_link_directory
  clone: copy hidden paths at local clone
  dir-iterator: add flags parameter to dir_iterator_begin
  dir-iterator: refactor state machine model
  dir-iterator: use warning_errno when possible
  dir-iterator: add tests for dir-iterator API
  clone: better handle symlinked files at .git/objects/
  clone: test for our behavior on odd objects/* content

diff --cc Makefile
Simple merge

diff --cc builtin/clone.c
Simple merge

diff --cc t/helper/test-tool.c
Simple merge

diff --cc t/helper/test-tool.h
Simple merge