Hello

I'm having some issues regarding the features check, when build Boost using OpenWRT GCC 5.3.0 cross-compiler for armv7. I'm building against musl. 

I have passed -std=c++14 to the cxxflags, but it seems to have no effect.

This is the features output

    - 32-bit                   : yes
    - arm                      : yes
    - symlinks supported       : yes
    - C++11 mutex              : yes
    - lockfree boost::atomic_flag : no
    - Boost.Config Feature Check: cxx11_auto_declarations : no
    - Boost.Config Feature Check: cxx11_constexpr : no
    - Boost.Config Feature Check: cxx11_defaulted_functions : no
    - Boost.Config Feature Check: cxx11_final : no
    - Boost.Config Feature Check: cxx11_hdr_tuple : no
    - Boost.Config Feature Check: cxx11_lambdas : no
    - Boost.Config Feature Check: cxx11_noexcept : no
    - Boost.Config Feature Check: cxx11_nullptr : no
    - Boost.Config Feature Check: cxx11_rvalue_references : no
    - Boost.Config Feature Check: cxx11_template_aliases : no
    - Boost.Config Feature Check: cxx11_thread_local : no
    - Boost.Config Feature Check: cxx11_variadic_templates : no
    - has_icu builds           : no
warning: Graph library does not contain MPI-based parallel components.
note: to enable them, add "using mpi ;" to your user-config.jam
    - zlib                     : yes
    - iconv (libc)             : no
    - iconv (separate)         : yes
    - icu                      : no
    - icu (lib64)              : no
    - native-atomic-int32-supported : yes
    - pthread-supports-robust-mutexes : yes
    - compiler-supports-visibility : yes
    - gcc visibility           : yes
    - long double support      : yes
    - zlib                     : yes

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