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/Make_dos.mak b/src/testdir/Make_dos.mak
index 6bb0577..8c0169b 100644
--- a/src/testdir/Make_dos.mak
+++ b/src/testdir/Make_dos.mak
@@ -37,6 +37,7 @@
 		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 \