(diff_wc_wc): Remove the arbritrary diff detection from here to ... (do_diff): ... its caller, here. Trigger behavior from working-working revision instead of overloading base-working diff in diff_wc_wc.
Reinstate the check for unsupported specific revisions from <= 1.7 in diff_wc_wc, instead of always running the arbritrary diff.
* subversion/libsvn_client/diff_local.c New file, based on diff.c (do_arbitrary_files_diff): Remove ignore properties and force binary code. This is handled by the diff callbacks.
* subversion/svn/diff-cmd.c (svn_cl__diff): Request working working diff.