patch 8.0.0643: when a pattern search is slow Vim becomes unusable

Problem:    When 'hlsearch' is set and matching with the last search pattern
            is very slow, Vim becomes unusable.  Cannot quit search by
            pressing CTRL-C.
Solution:   When the search times out set a flag and don't try again.  Check
            for timeout and CTRL-C in NFA loop that adds states.
diff --git a/src/regexp.h b/src/regexp.h
index 79c1e7d..a3526e6 100644
--- a/src/regexp.h
+++ b/src/regexp.h
@@ -165,8 +165,8 @@
 {
     regprog_T	*(*regcomp)(char_u*, int);
     void	(*regfree)(regprog_T *);
-    int		(*regexec_nl)(regmatch_T*, char_u*, colnr_T, int);
-    long	(*regexec_multi)(regmmatch_T*, win_T*, buf_T*, linenr_T, colnr_T, proftime_T*);
+    int		(*regexec_nl)(regmatch_T *, char_u *, colnr_T, int);
+    long	(*regexec_multi)(regmmatch_T *, win_T *, buf_T *, linenr_T, colnr_T, proftime_T *, int *);
     char_u	*expr;
 };