Merge branch 'da/difftool-updates'

Merge branch 'da/difftool-updates'

"git difftool --dir-diff" learned to use symbolic links to prepare
temporary copy of the working tree when available.

* da/difftool-updates:
  difftool: silence warning
  Add Code Compare v2.80.4 as a merge / diff tool for Windows
  mergetool,difftool: Document --tool-help consistently
  difftool: Disable --symlinks on cygwin
  difftool: Handle compare() returning -1
  difftool: Wrap long lines for readability
  difftool: Check all return codes from compare()
  difftool: Handle finding mergetools/ in a path with spaces
  difftool: Use symlinks when diffing against the worktree
  difftool: Call the temp directory "git-difftool"
  difftool: Move option values into a hash
  difftool: Eliminate global variables
  difftool: Simplify print_tool_help()