diff --git a/include/boost/regex/v4/instances.hpp b/include/boost/regex/v4/instances.hpp
index 8f07c252..d0238226 100644
--- a/include/boost/regex/v4/instances.hpp
+++ b/include/boost/regex/v4/instances.hpp
@@ -57,41 +57,23 @@ template class BOOST_REGEX_DECL reg_expression< BOOST_REGEX_CHAR_T >;
 
 #pragma option pop
 
-#elif defined(BOOST_MSVC)
+#elif defined(BOOST_MSVC) || defined(__GNUC__)
 
 #  ifndef BOOST_REGEX_INSTANTIATE
 #     define template extern template
 #  endif
 
-#pragma warning(push)
-#pragma warning(disable : 4251 4231 4660)
+#  ifdef BOOST_MSVC
+#     pragma warning(push)
+#     pragma warning(disable : 4251 4231 4660)
+#  endif
 
 template class BOOST_REGEX_DECL reg_expression< BOOST_REGEX_CHAR_T >;
 
-#pragma warning(pop)
-
-#  ifdef template
-#     undef template
+#  ifdef BOOST_MSVC
+#     pragma warning(pop)
 #  endif
 
-#elif !defined(BOOST_REGEX_HAS_DLL_RUNTIME)
-
-//
-// for each [member] function declare a full specialisation of that
-// [member] function, then instantiate it in one translation unit.
-// This is not guarenteed to work according to the standard, but in
-// practice it should work for all compilers (unless they use a realy
-// perverse name mangling convention).  Unfortunately this approach
-// does *not* work for Win32 style import/export, because that can
-// alter the class layout.
-//
-
-#  ifndef BOOST_REGEX_INSTANTIATE
-#     define template template<>
-#  endif
-
-template unsigned int BOOST_REGEX_CALL reg_expression<BOOST_REGEX_CHAR_T>::set_expression(const BOOST_REGEX_CHAR_T* p, const BOOST_REGEX_CHAR_T* end, reg_expression<BOOST_REGEX_CHAR_T>::flag_type f);
-
 #  ifdef template
 #     undef template
 #  endif
diff --git a/include/boost/regex/v4/match_flags.hpp b/include/boost/regex/v4/match_flags.hpp
index b12c3519..28ad1065 100644
--- a/include/boost/regex/v4/match_flags.hpp
+++ b/include/boost/regex/v4/match_flags.hpp
@@ -123,6 +123,7 @@ using regex_constants::match_nosubs;
 using regex_constants::format_all;
 using regex_constants::format_sed;
 using regex_constants::format_perl;
+using regex_constants::format_default;
 using regex_constants::format_no_copy;
 using regex_constants::format_first_only;
 //using regex_constants::format_is_if;
diff --git a/include/boost/regex/v4/sub_match.hpp b/include/boost/regex/v4/sub_match.hpp
index b74eb224..b67dd3ac 100644
--- a/include/boost/regex/v4/sub_match.hpp
+++ b/include/boost/regex/v4/sub_match.hpp
@@ -51,16 +51,16 @@ struct sub_match : public std::pair<BidiIterator, BidiIterator>
    }
    difference_type BOOST_REGEX_CALL length()const
    {
-      difference_type n = boost::re_detail::distance((BidiIterator)first, (BidiIterator)second);
+      difference_type n = boost::re_detail::distance((BidiIterator)this->first, (BidiIterator)this->second);
       return n;
    }
    std::basic_string<value_type> str()const
    {
       std::basic_string<value_type> result;
-      std::size_t len = boost::re_detail::distance((BidiIterator)first, (BidiIterator)second);
+      std::size_t len = boost::re_detail::distance((BidiIterator)this->first, (BidiIterator)this->second);
       result.reserve(len);
-      BidiIterator i = first;
-      while(i != second)
+      BidiIterator i = this->first;
+      while(i != this->second)
       {
          result.append(1, *i);
          ++i;