Matched: add boxed_clone() method

We may need to clone a Matches instance but it's impossible without
putting it behind a pointer (object safety).

Signed-off-by: Tibor Benke <tibor.benke@balabit.com>

src/matcher/matcher/mod.rs

@@ -7,4 +7,5 @@ pub mod builder;
 pub trait Matcher: fmt::Debug {
     fn parse<'a, 'b>(&'a self, text: &'b str) -> Option<MatchResult<'a, 'b>>;
     fn add_pattern(&mut self, pattern: Pattern);
+    fn boxed_clone(&self) -> Box<Matcher>;
 }

src/matcher/trie/matcher.rs

@@ -10,4 +10,7 @@ impl Matcher for ParserTrie {
     fn add_pattern(&mut self, pattern: Pattern) {
         self.insert(pattern);
     }
+    fn boxed_clone(&self) -> Box<Matcher> {
+        Box::new(self.clone())
+    }
 }