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/proto/eval.pro b/src/proto/eval.pro
index 22b8b18..b807baf 100644
--- a/src/proto/eval.pro
+++ b/src/proto/eval.pro
@@ -133,6 +133,7 @@
 int store_session_globals __ARGS((FILE *fd));
 void last_set_msg __ARGS((scid_T scriptID));
 void ex_oldfiles __ARGS((exarg_T *eap));
+void reset_v_option_vars __ARGS((void));
 int modify_fname __ARGS((char_u *src, int *usedlen, char_u **fnamep, char_u **bufp, int *fnamelen));
 char_u *do_string_sub __ARGS((char_u *str, char_u *pat, char_u *sub, char_u *flags));
 /* vim: set ft=c : */