patch 7.4.786
Problem:    It is not possible for a plugin to adjust to a changed setting.
Solution:   Add the OptionSet autocommand event. (Christian Brabandt)
diff --git a/src/testdir/Makefile b/src/testdir/Makefile
index 1a3ff85..4d5aea7 100644
--- a/src/testdir/Makefile
+++ b/src/testdir/Makefile
@@ -35,6 +35,7 @@
 		test104.out test105.out test106.out test107.out \
 		test_argument_0count.out \
 		test_argument_count.out \
+		test_autocmd_option.out \
 		test_autoformat_join.out \
 		test_breakindent.out \
 		test_changelist.out \