systemd/INSTALL

Usual options for udev installed in the root filesystem are:
  ./configure \
    --prefix=/usr \
    --sysconfdir=/etc \
    --sbindir=/sbin \
    --libdir=/usr/lib64 \
    --with-rootlibdir=/lib64 \
    --libexecdir=/lib/udev \
    --with-selinux

The options used in a RPM spec file usually look like:
  %configure \
    --prefix=%{_prefix} \
    --sysconfdir=%{_sysconfdir} \
    --sbindir=/sbin \
    --libdir=%{_libdir} \
    --with-rootlibdir=/%{_lib} \
    --libexecdir=/lib/udev \
    --with-selinux

The defined location for scripts and binaries which are called
from rules is /lib/udev/ on all systems and architectures. Any
other location will break other packages, who rightfully expect
the /lib/udev/ directory, to install their rule helper and udev
rule files.

It is possible to use the /lib/udev/devices/ directory to place
device nodes, directories and symlinks, which are copied to /dev/
at every bootup. That way, nodes for devices which can not be
detected automatically, or are activated on-demand by opening the
pre-existing device node, will be available.

Default udev rules and persistent device naming rules may be required
by other software that depends on the data udev collects from the
devices.