compiling boost with non-default g++

[mi at aldan.algebra.com]

Hello!

I wanted to build devel/boost-libs with g++48, but the port kept using the stock 
g++ no matter, what I tried.

It seems 
<http://boost.2283326.n4.nabble.com/Configuring-multiple-versions-of-gcc-td2692129.html>, 
for non-default version of g++, the user-config.jam needs to be altered. Whether 
boost-all/compiled.mk is the right place for this setting, is up to you to 
decide... This seems to be working for me -- the port is building as I type this 
-- but might it break some other consumer of compiled.mk?

    Index: compiled.mk
    ===================================================================
    --- compiled.mk (revision 316411)
    +++ compiled.mk (working copy)
    @@ -58,3 +59,6 @@
      post-patch:
             @${REINPLACE_CMD} -e 's|${PORTVERSION}|${BOOST_SHARED_LIB_VER}|g' \
                     ${WRKSRC}/Jamroot
    +.if ${BOOST_TOOLSET} == gcc
    +       @${ECHO} "using gcc : : ${CXX} ;" >>
    ${WRKSRC}/tools/build/v2/user-config.jam
    +.endif

Yours,

    -mi