[Clfs-support] multilib unwantedly derived from common

[Charlie Brown]

Hi,
I've been following the systemd branch, and noticed that some recent
changes in common didn't get into the x86_64 multilib book, like
commit 8e3e941 and commit ab871d98.
Is that a mistake?

The multilib book has to take care of /usr/lib64 and /lib64, so it
uses different commands when configuring and creating files. But there
are times that it should follow the changes in common/ directory. I
guess it has been a headache for maintainers for a while...

Thank you for your work!

Sincerely,
王文鑫
Charlie