Boost.Chrono: Try to solve issue

 Test output: daw-msvc71 - chrono - arithmetic_pass_shared / msvc-7.1
Rev 67704 / Thu, 6 Jan 2011 02:00:52 +0000
Report Time: Thu, 6 Jan 2011 12:15:03 +0000

Compile [2011-01-06 04:45:50 UTC]: fail

    call "C:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\bin\vcvars32.bat"  >nul
cl /Zm800 -nologo @"C:\boost_testing_trunk\results\boost\bin.v2\libs\chrono\test\arithmetic_pass_shared.test\msvc-7.1\debug\asynch-exceptions-on\threading-multi\duration\arithmetic_pass.obj.rsp" 

arithmetic_pass.cpp
..\boost\chrono\duration.hpp(443) : error C2039: 'duration_cast' : is not a member of 'boost'
        ..\libs\chrono\test\duration\arithmetic_pass.cpp(69) : see reference to function template instantiation 'boost::chrono::duration<Rep>::duration<boost::int_least32_t,boost::ratio<N>>(const boost::chrono::duration<boost::int_least32_t,Period> &,boost::enable_if_c<B,T>::type *)' being compiled
        with
        [
            Rep=boost::int_least64_t,
            N=0x03c,
            Period=boost::ratio<0x03c>,
            B=true,
            T=void
        ]
..\boost\chrono\duration.hpp(443) : error C2275: 'boost::chrono::duration<Rep>' : illegal use of this type as an expression
        with
        [
            Rep=boost::int_least64_t
        ]
..\boost\chrono\duration.hpp(443) : fatal error C1903: unable to recover from previous error(s); stopping compilation


[SVN r67719]

libs/chrono

@@ -1 +1 @@
-Subproject commit 4dcb3d699e1a5dfd4bf5c7a60660b3517b4d2d03
+Subproject commit cc23c75fd46480a22245c52d4140bd6e94e75cc2