updated for version 7.4.593
Problem:    Crash when searching for "x\{0,90000}". (Dominique Pelle)
Solution:   Bail out from the NFA engine when the max limit is much higher
            than the min limit.
diff --git a/src/regexp.c b/src/regexp.c
index d36ac49..bae547c 100644
--- a/src/regexp.c
+++ b/src/regexp.c
@@ -8081,7 +8081,8 @@
      * First try the NFA engine, unless backtracking was requested.
      */
     if (regexp_engine != BACKTRACKING_ENGINE)
-        prog = nfa_regengine.regcomp(expr, re_flags);
+        prog = nfa_regengine.regcomp(expr,
+		re_flags + (regexp_engine == AUTOMATIC_ENGINE ? RE_AUTO : 0));
     else
 	prog = bt_regengine.regcomp(expr, re_flags);
 
@@ -8105,16 +8106,14 @@
 #endif
 	/*
 	 * If the NFA engine failed, try the backtracking engine.
-	 * Disabled for now, both engines fail on the same patterns.
-	 * Re-enable when regcomp() fails when the pattern would work better
-	 * with the other engine.
-	 *
+	 * The NFA engine also fails for patterns that it can't handle well
+	 * but are still valid patterns, thus a retry should work.
+	 */
 	if (regexp_engine == AUTOMATIC_ENGINE)
 	{
+	    regexp_engine = BACKTRACKING_ENGINE;
 	    prog = bt_regengine.regcomp(expr, re_flags);
-	    regexp_engine == BACKTRACKING_ENGINE;
 	}
-	 */
     }
 
     if (prog != NULL)