[boost] how to pass -std=c++14 to b2 while building boost libraries

Subject: [boost] how to pass -std=c++14 to b2 while building boost libraries
From: Frédéric Bron (frederic.bron_at_[hidden])
Date: 2015-09-30 04:38:56

Hi,

I would like to build a c++14 version of boost libraries on my system.
I have the intel compiler (15.0.3) on a x86_64 linux machine
(2.6.32-279.19.1.el6.x86_64).

I do the following:

1. build b2

CC="icc" CFLAGS="-O2 -DNDEBUG -xhost" CXX="icpc" CXXFLAGS="-O2
-DNDEBUG -xhost -std=c++14" AR="ar" AS="as" RANLIB="ranlib"
./bootstrap.sh --without-icu
--prefix=/myusr/icc-15.0.3-c++14-release/boost
--with-toolset=intel-linux

2. edit user-config.jam

My user-config.jam, located in the boost source directory contains:
using intel-linux : : icpc : <compilerflags>-xhost <compilerflags>-std=c++14 ;

3. run b2

./b2 -d2 -j16 -sBZIP2_INCLUDE=/myusr/icc-15.0.3-c++14-release/bzip2/include
-sBZIP2_LIBPATH=/myusr/icc-15.0.3-c++14-release/bzip2/lib
-sZLIB_INCLUDE=/myusr/icc-15.0.3-c++14-release/zlib/include
-sZLIB_LIBPATH=/myusr/icc-15.0.3-c++14-release/zlib/lib
--layout=system --user-config=user-config.jam --without-mpi
--without-python --without-context --without-coroutine link=static
threading=multi runtime-link=shared target-os=linux address-model=64
variant=release install

The problem I see is that the flag -std=c++14 is not passed to the
compiler. For example, this is an output of b2:

    "icpc" -c -xc++ -w1 -inline-level=2 -O3 -ip -pthread -m64
-DBOOST_ALL_NO_LIB=1 -DBOOST_FILESYSTEM_STATIC_LINK=1
-DBOOST_SYSTEM_STATIC_LINK=1 -DNDEBUG -I"."   -c -o
"bin.v2/libs/filesystem/build/intel-linux/release/link-static/threading-multi/codecvt_error_category.o"
"libs/filesystem/src/codecvt_error_category.cpp"

no trace of -std=c++14 flag.

How can I send that flag to the compiler?
Apparently, the problem is the same when using g++ 5.2.0.

Frédéric