updated for version 7.3.1149
Problem:    New regexp engine: Matching plain text could be faster.
Solution:   Detect a plain text match and handle it specifically.  Add
            vim_regfree().
diff --git a/src/regexp.h b/src/regexp.h
index 1842282..976927e 100644
--- a/src/regexp.h
+++ b/src/regexp.h
@@ -89,6 +89,7 @@
 
     int			reganch;	/* pattern starts with ^ */
     int			regstart;	/* char at start of pattern */
+    char_u		*match_text;	/* plain text to match with */
 
     int			has_zend;	/* pattern contains \ze */
     int			has_backref;	/* pattern contains \1 .. \9 */
@@ -147,6 +148,7 @@
 struct regengine
 {
     regprog_T	*(*regcomp)(char_u*, int);
+    void	(*regfree)(regprog_T *);
     int		(*regexec)(regmatch_T*, char_u*, colnr_T);
 #if defined(FEAT_MODIFY_FNAME) || defined(FEAT_EVAL) \
 	|| defined(FIND_REPLACE_DIALOG) || defined(PROTO)