$ clang++ --version
Apple clang version 3.0 (tags/Apple/clang-211.10.1) (based on LLVM 3.0svn)
Target: x86_64-apple-darwin11.1.0
Thread model: posix

$ llvm-g++-4.2 --version
i686-apple-darwin11-llvm-g++-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.1.00)
Copyright (C) 2007 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ g++ --version
i686-apple-darwin11-llvm-g++-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.1.00)
Copyright (C) 2007 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ clang++ sample.cpp -I/opt/local/include -L/opt/local/lib -lboost_system-mt -lboost_regex-mt -licudata -licui18n -licuuc
In file included from sample.cpp:2:
In file included from /opt/local/include/boost/regex.hpp:31:
In file included from /opt/local/include/boost/regex/v4/regex.hpp:70:
/opt/local/include/boost/regex/v4/basic_regex_creator.hpp:1027:34: warning: equality comparison with extraneous
      parentheses [-Wparentheses]
            else if((state->type == syntax_element_long_set_rep)) 
                     ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/local/include/boost/regex/v4/basic_regex_creator.hpp:1027:34: note: remove extraneous parentheses around the
      comparison to silence this warning
            else if((state->type == syntax_element_long_set_rep)) 
                    ~            ^                             ~
/opt/local/include/boost/regex/v4/basic_regex_creator.hpp:1027:34: note: use '=' to turn this equality comparison into
      an assignment
            else if((state->type == syntax_element_long_set_rep)) 
                                 ^~
                                 =
/opt/local/include/boost/regex/v4/basic_regex_creator.hpp:1328:28: warning: equality comparison with extraneous
      parentheses [-Wparentheses]
               if((p->type == syntax_element_recurse))
                   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
/opt/local/include/boost/regex/v4/basic_regex_creator.hpp:1328:28: note: remove extraneous parentheses around the
      comparison to silence this warning
               if((p->type == syntax_element_recurse))
                  ~        ^                        ~
/opt/local/include/boost/regex/v4/basic_regex_creator.hpp:1328:28: note: use '=' to turn this equality comparison into
      an assignment
               if((p->type == syntax_element_recurse))
                           ^~
                           =
2 warnings generated.
Undefined symbols for architecture x86_64:
  "boost::icu_regex_traits::isctype(int, unsigned long long) const", referenced from:
      boost::re_detail::perl_matcher<boost::u8_to_u32_iterator<char const*, int>, std::allocator<boost::sub_match<boost::u8_to_u32_iterator<char const*, int> > >, boost::icu_regex_traits>::find_restart_word() in cc-gArVZq.o
      boost::u8_to_u32_iterator<char const*, int> boost::re_detail::re_is_set_member<boost::u8_to_u32_iterator<char const*, int>, int, boost::icu_regex_traits, unsigned long long>(boost::u8_to_u32_iterator<char const*, int>, boost::u8_to_u32_iterator<char const*, int>, boost::re_detail::re_set_long<unsigned long long> const*, boost::re_detail::regex_data<int, boost::icu_regex_traits> const&, bool) in cc-gArVZq.o
      boost::re_detail::perl_matcher<boost::u8_to_u32_iterator<char const*, int>, std::allocator<boost::sub_match<boost::u8_to_u32_iterator<char const*, int> > >, boost::icu_regex_traits>::match_word_boundary() in cc-gArVZq.o
      boost::re_detail::perl_matcher<boost::u8_to_u32_iterator<char const*, int>, std::allocator<boost::sub_match<boost::u8_to_u32_iterator<char const*, int> > >, boost::icu_regex_traits>::match_within_word() in cc-gArVZq.o
      boost::re_detail::perl_matcher<boost::u8_to_u32_iterator<char const*, int>, std::allocator<boost::sub_match<boost::u8_to_u32_iterator<char const*, int> > >, boost::icu_regex_traits>::match_word_start() in cc-gArVZq.o
      boost::re_detail::perl_matcher<boost::u8_to_u32_iterator<char const*, int>, std::allocator<boost::sub_match<boost::u8_to_u32_iterator<char const*, int> > >, boost::icu_regex_traits>::match_word_end() in cc-gArVZq.o
  "boost::re_detail::icu_regex_traits_implementation::do_transform(int const*, int const*, icu_46::Collator const*) const", referenced from:
      boost::re_detail::icu_regex_traits_implementation::transform_primary(int const*, int const*) const in cc-gArVZq.o
      boost::re_detail::icu_regex_traits_implementation::transform(int const*, int const*) const in cc-gArVZq.o
  "boost::basic_regex<int, boost::icu_regex_traits>::do_assign(int const*, int const*, unsigned int)", referenced from:
      boost::basic_regex<int, boost::icu_regex_traits>::assign(int const*, int const*, unsigned int) in cc-gArVZq.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

$ g++ sample.cpp -I/opt/local/include -L/opt/local/lib -lboost_system-mt -lboost_regex-mt -licudata -licui18n -licuuc
Undefined symbols for architecture x86_64:
  "boost::basic_regex<int, boost::icu_regex_traits>::do_assign(int const*, int const*, unsigned int)", referenced from:
      boost::basic_regex<int, boost::icu_regex_traits>::assign(int const*, int const*, unsigned int)in ccTZh2is.o
  "boost::icu_regex_traits::isctype(int, unsigned long long) const", referenced from:
      boost::re_detail::perl_matcher<boost::u8_to_u32_iterator<char const*, int>, std::allocator<boost::sub_match<boost::u8_to_u32_iterator<char const*, int> > >, boost::icu_regex_traits>::match_word_end()in ccTZh2is.o
      boost::re_detail::perl_matcher<boost::u8_to_u32_iterator<char const*, int>, std::allocator<boost::sub_match<boost::u8_to_u32_iterator<char const*, int> > >, boost::icu_regex_traits>::match_word_start()in ccTZh2is.o
      boost::re_detail::perl_matcher<boost::u8_to_u32_iterator<char const*, int>, std::allocator<boost::sub_match<boost::u8_to_u32_iterator<char const*, int> > >, boost::icu_regex_traits>::match_within_word()in ccTZh2is.o
      boost::re_detail::perl_matcher<boost::u8_to_u32_iterator<char const*, int>, std::allocator<boost::sub_match<boost::u8_to_u32_iterator<char const*, int> > >, boost::icu_regex_traits>::match_word_boundary()in ccTZh2is.o
      boost::u8_to_u32_iterator<char const*, int> boost::re_detail::re_is_set_member<boost::u8_to_u32_iterator<char const*, int>, int, boost::icu_regex_traits, unsigned long long>(boost::u8_to_u32_iterator<char const*, int>, boost::u8_to_u32_iterator<char const*, int>, boost::re_detail::re_set_long<unsigned long long> const*, boost::re_detail::regex_data<int, boost::icu_regex_traits> const&, bool)in ccTZh2is.o
      boost::re_detail::perl_matcher<boost::u8_to_u32_iterator<char const*, int>, std::allocator<boost::sub_match<boost::u8_to_u32_iterator<char const*, int> > >, boost::icu_regex_traits>::find_restart_word()in ccTZh2is.o
  "boost::re_detail::icu_regex_traits_implementation::do_transform(int const*, int const*, icu_46::Collator const*) const", referenced from:
      boost::re_detail::icu_regex_traits_implementation::transform(int const*, int const*) constin ccTZh2is.o
      boost::re_detail::icu_regex_traits_implementation::transform_primary(int const*, int const*) constin ccTZh2is.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status