On many distros, getting multilib support is very straight forward. There exists a guide that can act as a replacement for LFS: compiling and configuring a system that can boot, run, and compile software; and also have that same ability with 32-bit. It acts to form the basis that will allow you to follow any of the instructions laid out in the Steam and Wine chapters.
Such a guide is maintained by Thomas Trepl at https://www.linuxfromscratch.org/~thomas/multilib-systemd-m32. This only covers installing 32-bit support along with 64-bit. If you want x32-bit support, which is not needed for this book, follow https://www.linuxfromscratch.org/~thomas/multilib-systemd.
The links above, however, are rolling release and are rendered frequently. The known version of MLFS to work with this version of GLFS is 6fac5d60ac4da40e5d027ffcac5c0d0f32171f5f. You can render it by following the instructions below.
First, install
Git, then clone the LFS repo and switch to the multilib branch:
git clone https://git.linuxfromscratch.org/lfs.git mlfs && cd mlfs && git checkout multilib
Now switch to the stable git hash:
git checkout 6fac5d60ac4da40e5d027ffcac5c0d0f32171f5f && git merge --no-commit 99d3c4a4c703a522509e087fb7c9dd7893241978
Now inspect the INSTALL file to check
for the needed dependencies in order to render the book. Once you
have ensured you have installed everything, render the book:
make -j1 REV=systemd ARCH=ml_32
This will render the book in ~/public_html/lfs-systemd. You can change how
much multilib support you wish to render the book with by changing
the ARCH variable's value. The above
command will render 64-bit and 32-bit support but leaves out
x32-bit support, which is not needed for this book. If you want to
get that support too, change ARCH=ml_32 to ARCH=ml_all. You can then point to the HTML
using a browser like
Firefox or
Lynx.
For Firefox, type in the search
bar: file:///home/,
and replace <username>/public_html/lfs-systemd/index.html<username> with the name of
the username you rendered the book with.
For Lynx, run the following:
lynx ~/public_html/lfs-systemd/index.html
The same principles of compiling for 32-bit in that book will also apply to this book as well. If you haven't already, read Important Information to check what basic principles still apply in this book when targeting 32-bit.
Furthermore, read Which Instructions to Follow to find out which instructions to follow.