Laurent,
I would suggest you start over using the libgfortran as your
example. Geoffrey Keating created the config/multi.m4 file which
dramatically simplified how the multilib could be implemented.
If I recall correctly from when I helped clean up some of
the residual multilib problems (so they used multi.m4), you
just need in configure.ac...
AM_ENABLE_MULTILIB(, ..)
...and for the 'Calculate toolexeclibdir' section...
toolexeclibdir='$(toolexecdir)/$(gcc_version)$(MULTISUBDIR)'
...and...
if test ${multilib} = yes; then
multilib_arg="--enable-multilib"
else
multilib_arg=
fi
...before you write your Makefile in configure.ac. You might also
need the lines for multi_os_directory as well. When you regenerate
the aclocal.m4 or configure don't forget to use '-I ../config' for
autoconf so that it can find the multi.m4 in the top level config
directory.
Jack
