Merge branch 'jc/maint-blank-at-eof' into next

Merge branch 'jc/maint-blank-at-eof' into next

* jc/maint-blank-at-eof:
  diff -B: colour whitespace errors
  diff.c: emit_add_line() takes only the rest of the line
  diff.c: split emit_line() from the first char and the rest of the line
  diff.c: shuffling code around
  diff --whitespace: fix blank lines at end