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/evalfunc.c b/src/evalfunc.c
index 8167abd..2bbdefc 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -9281,7 +9281,7 @@
 
     pos = save_cursor = curwin->w_cursor;
     subpatnum = searchit(curwin, curbuf, &pos, dir, pat, 1L,
-				options, RE_SEARCH, (linenr_T)lnum_stop, &tm);
+			   options, RE_SEARCH, (linenr_T)lnum_stop, &tm, NULL);
     if (subpatnum != FAIL)
     {
 	if (flags & SP_SUBPAT)
@@ -9619,7 +9619,7 @@
     for (;;)
     {
 	n = searchit(curwin, curbuf, &pos, dir, pat, 1L,
-					   options, RE_SEARCH, lnum_stop, &tm);
+				     options, RE_SEARCH, lnum_stop, &tm, NULL);
 	if (n == FAIL || (firstpos.lnum != 0 && EQUAL_POS(pos, firstpos)))
 	    /* didn't find it or found the first match again: FAIL */
 	    break;