Merge branch 'jk/diff-patch-dry-run-cleanup'

Finishing touches to fixes to the recent regression in "git diff -w --quiet" and anything that needs to internally generate patch to see if it turns empty. * jk/diff-patch-dry-run-cleanup: diff: simplify run_external_diff() quiet logic diff: drop dry-run redirection to /dev/null diff: replace diff_options.dry_run flag with NULL file diff: drop save/restore of color_moved in dry-run mode diff: send external diff output to diff_options.file