Otherwise it will try to guess the log directory, and the guess might
not be the same if chroot builds are enabled or not.
The gruesome details from m4/sudo.m4:
````
dnl
dnl Where the I/O log files go, use /var/log/sudo-io if
dnl /var/log exists, else /{var,usr}/adm/sudo-io
dnl
AC_DEFUN([SUDO_IO_LOGDIR], [
AC_MSG_CHECKING(for I/O log dir location)
if test "${with_iologdir-yes}" != "yes"; then
iolog_dir="$with_iologdir"
elif test -d "/var/log"; then
iolog_dir="/var/log/sudo-io"
elif test -d "/var/adm"; then
iolog_dir="/var/adm/sudo-io"
else
iolog_dir="/usr/adm/sudo-io"
fi
if test "${with_iologdir}" != "no"; then
SUDO_DEFINE_UNQUOTED(_PATH_SUDO_IO_LOGDIR, "$iolog_dir")
fi
AC_MSG_RESULT($iolog_dir)
])dnl
````