Fairly trivial patch for bug report 1526472.

[SVN r34680]

include/boost/regex/v4/regex_token_iterator.hpp

@@ -110,6 +110,7 @@ public:
          result.first = first;
          result.second = end;
          result.matched = (first != end);
+         N = -1;
          return true;
       }
       return false;

include/boost/regex/v4/u32regex_token_iterator.hpp

@@ -107,6 +107,7 @@ public:
          result.first = first;
          result.second = end;
          result.matched = (first != end);
+         N = -1;
          return true;
       }
       return false;