installworld fails on missing tzsetup when WITHOUT_DIALOG is set

Hi,

installworld fails on missing tzsetup when src.conf has WITHOUT_DIALOG=
and delete-old was previously run to remove tzsetup from the system.

mkdir -p /tmp/install.8gNIwAFV
progs=$(for prog in [ awk cap_mkdb cat chflags chmod chown cmp cp
date echo egrep find grep id install   ln make mkdir mtree mv pwd_mkdb
 rm sed services_mkdb sh strip sysctl test true uname wc zic tzsetup
makewhatis; do  if progpath=`which $prog`; then  echo $progpath;  else
 echo "Required tool $prog not found in PATH." >&2;  exit 1;  fi;
done);  libs=$(ldd -f "%o %p\n" -f "%o %p\n" $progs 2>/dev/null | sort
-u |  while read line; do  set -- $line;  if [ "$2 $3" != "not found"
]; then  echo $2;  else  echo "Required library $1 not found." >&2;
exit 1;  fi;  done);  cp $libs $progs /tmp/install.8gNIwAFV
Required tool tzsetup not found in PATH.
*** Error code 1

tzsetup is used in share/zoneinfo/Makefile when ${DESTDIR}/var/db/zoneinfo
exists and some other conditions.

In my case, I don't have /var/db/zoneinfo since I manually created a symlink
from /usr/share/zoneinfo/... to /etc/localtime instead of using tzsetup.

A possible fix is to add a WITHOUT_TZSETUP knob and not use
tzsetup when the knob is enabled.

https://github.com/guyyur/freebsd-src_patches/blob/master/without_tzsetup_knob.patch
(patch doesn't include regenerating src.conf.5)

Thanks,
Guy