Merge branch 'mh/check-attr-relative'

Merge branch 'mh/check-attr-relative'

* mh/check-attr-relative: (29 commits)
  test-path-utils: Add subcommand "prefix_path"
  test-path-utils: Add subcommand "absolute_path"
  git-check-attr: Normalize paths
  git-check-attr: Demonstrate problems with relative paths
  git-check-attr: Demonstrate problems with unnormalized paths
  git-check-attr: test that no output is written to stderr
  Rename git_checkattr() to git_check_attr()
  git-check-attr: Fix command-line handling to match docs
  git-check-attr: Drive two tests using the same raw data
  git-check-attr: Add an --all option to show all attributes
  git-check-attr: Error out if no pathnames are specified
  git-check-attr: Process command-line args more systematically
  git-check-attr: Handle each error separately
  git-check-attr: Extract a function error_with_usage()
  git-check-attr: Introduce a new variable
  git-check-attr: Extract a function output_attr()
  Allow querying all attributes on a file
  Remove redundant check
  Remove redundant call to bootstrap_attr_stack()
  Extract a function collect_all_attrs()
  ...