devel/boost issues regarding boost/chrono/duration.hpp constexpr definitions with clang

[Gergely CZUCZY]

Hello,

Could you please update boost to 1.55? There's seems to be some issues
with the current version, which might be fixed later.

Namely, on a 9.x default install, built with defaults (gcc as defcc),
when one is trying to include boost/thread/shared_mutex.hpp and build
that file with clang:

--- BEGIN boostmtx.cc ---
#include <boost/thread/shared_mutex.hpp>

int main() { return 0; }
--- END boostmtx.cc ---

And when trying to build it:
$ CXXFLAGS="-Werror -pedantic -std=c++11 -I/usr/local/include" CXX=clang++ make boostmtx
clang++ -Werror -pedantic -std=c++11 -I/usr/local/include  boostmtx.cc  -o boostmtx
In file included from boostmtx.cc:1:
In file included from /usr/local/include/boost/thread/shared_mutex.hpp:21:
In file included from /usr/local/include/boost/thread/pthread/shared_mutex.hpp:13:
In file included from /usr/local/include/boost/thread/mutex.hpp:16:
In file included from /usr/local/include/boost/thread/pthread/mutex.hpp:12:
In file included from /usr/local/include/boost/thread/locks.hpp:18:
In file included from /usr/local/include/boost/chrono/time_point.hpp:33:
/usr/local/include/boost/chrono/duration.hpp:667:28: error: 'constexpr' non-static member function will not be implicitly 'const' in
      C++1y; add 'const' to avoid a change in behavior [-Werror,-Wconstexpr-not-const]
      BOOST_CONSTEXPR bool operator()(const LhsDuration& lhs, const RhsDuration& rhs)
                           ^
                                                                                      const
/usr/local/include/boost/chrono/duration.hpp:677:28: error: 'constexpr' non-static member function will not be implicitly 'const' in
      C++1y; add 'const' to avoid a change in behavior [-Werror,-Wconstexpr-not-const]
      BOOST_CONSTEXPR bool operator()(const LhsDuration& lhs, const LhsDuration& rhs)
                           ^
                                                                                      const
/usr/local/include/boost/chrono/duration.hpp:686:28: error: 'constexpr' non-static member function will not be implicitly 'const' in
      C++1y; add 'const' to avoid a change in behavior [-Werror,-Wconstexpr-not-const]
      BOOST_CONSTEXPR bool operator()(const LhsDuration& lhs, const RhsDuration& rhs)
                           ^
                                                                                      const
/usr/local/include/boost/chrono/duration.hpp:696:28: error: 'constexpr' non-static member function will not be implicitly 'const' in
      C++1y; add 'const' to avoid a change in behavior [-Werror,-Wconstexpr-not-const]
      BOOST_CONSTEXPR bool operator()(const LhsDuration& lhs, const LhsDuration& rhs)
                           ^
                                                                                      const
4 errors generated.
*** [boostmtx] Error code 1



FreeBSD dirk.bealak.harmless.lan 9.2-STABLE FreeBSD 9.2-STABLE #0: Sat Sep 28 13:31:29 CEST 2013     toor at dirk.bealak.harmless.lan:/usr/obj/usr/src/sys/DIRK  amd64

Could you please look into this issue? This should pretty much work with the clang in base.

Best regards,
Gergely