Cross GCC (MULTILIB_OSDIRNAMES m32)

[evanation]

If build gcc with the --with-build-sysroot=$sysroot_dir parameter, then the
built gcc -m32 will look for libraries in $sysroot_dir/lib32 and
$sysroot_dir/usr/lib32, if there are such directories there. But if build
with the --without-headers parameter and without --with-build-sysroot then
how to make the assembled gcc -m32 look in $sysroot_dir/lib32? Only edit
gcc/config/i386/t-linux64 file?
My building parametres:
configure \
--build=$(../"$srcdir"/config.guess) \
--host=$(../"$srcdir"/config.guess) \
--target=$_target \
--prefix=$_prefix \
--with-sysroot=$_sysroot \
--with-newlib \
--disable-nls \
--enable-multilib \
--with-multilib-list=m64,m32,mx32 \
--disable-shared \
--disable-threads \
--enable-languages=c,c++

P.S. Sorry for my English