Merge branch 'nd/diff-stat-with-summary'

"git diff" and friends learned "--compact-summary" that shows the
information usually given with the "--summary" option on the same
line as the diffstat output of the "--stat" option (which saves
vertical space and keeps info on a single path at the same place).

* nd/diff-stat-with-summary:
  diff: add --compact-summary
  diff.c: refactor pprint_rename() to use strbuf

diff.h

@@ -93,6 +93,7 @@ struct diff_flags {
 	unsigned dirstat_by_line:1;
 	unsigned funccontext:1;
 	unsigned default_follow_renames:1;
+	unsigned stat_with_summary:1;
 };
 
 static inline void diff_flags_or(struct diff_flags *a,