Merge branch 'nd/diff-flush-before-warning' into maint

Avoid showing a warning message in the middle of a line of "git
diff" output.

* nd/diff-flush-before-warning:
  diff.c: flush stdout before printing rename warnings

diff.c

@@ -5454,6 +5454,7 @@ N_("you may want to set your %s variable to at least "
 
 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
 {
+	fflush(stdout);
 	if (degraded_cc)
 		warning(_(degrade_cc_to_c_warning));
 	else if (needed)