message: p4: Force use of UNIX diff, not some UI-diff tool.
diff: @@ -117,7 +117,8 @@ function git_touched_files() {
  # Set commands based on version control system
  case "$rcs" in
  p4) touched_files=p4_touched_files
  - single_file_diff=(p4 diff -d-u "{}") ;;
  + # force use of traditional text 'diff', not some other UI-diff tool
  + single_file_diff=(P4DIFF=diff p4 diff -d-u "{}") ;;
  git) touched_files=git_touched_files
  single_file_diff=(git diff -u --cached "{}") ;;
  *) { msg "Unsupported version control system: $rcs" ; exit 1;} ;;
  