[Boost-build] compiling boost with 2 versions of gcc

Subject: [Boost-build] compiling boost with 2 versions of gcc
From: Renaud Lepère (lepere.renaud_at_[hidden])
Date: 2013-11-16 07:10:55

I would like to use 2 different versions of gcc under windows (mingw 32 
bits, and mingw 64 bits) ; and i would like to be compile and use boost 
in both variants.

I have modified user-config.jam
using gcc : mingw64 : c:/mingw64/bin/g++ ;
using gcc : mingw32 : c:/mingw32/bin/g++ ;

but when i build boost for example using :
b2 gcc-mingw64 --with-filesystem stage
i ended with a file under stage\lib libboost_filesystem-mgw-mt-1_55.a  
that is independant of the version of gcc (32bits or 64bits).
ideally i would like to have two files : 
libboost_filesystem-mgw64-mt-1_55.a or libboost_filesystem-mgw32-mt-1_55.a

How can i solve my problem ?

Thanks,