speed up apt-get operations by not rebuilding the man-db cache

this apparently has little influence of man-page speed
the man-db cache is regenerated daily anyhow by a service / timer

src/build_dist

@@ -111,6 +111,9 @@ if [[ "$VARIANT" == "dietpi"* ]] ; then
     touch "$MNT_DIR"/opt/adsb/os.adsb.feeder.image
     touch "$MNT_DIR"/opt/adsb/adsb.im.passwd.and.keys
 
+    # speed up apt-get operations by not rebuilding the man-db cache:
+    rm -f "$MNT_DIR"/var/lib/man-db/auto-update
+
     # make systemd journal persistent for dietpi
     sed -i -e 's/.*Storage=.*/Storage=persistent/' "$MNT_DIR/etc/systemd/journald.conf"
     sed -i -e 's/.*RuntimeMaxUse=.*/RuntimeMaxUse=10M/' /etc/systemd/journald.conf

src/modules/adsb-feeder/start_chroot_script

@@ -14,6 +14,10 @@ install_cleanup_trap
 
 unpack /filesystem/root /
 
+# speed up apt-get operations by not rebuilding the man-db cache:
+debconf-set man-db/auto-update false || true
+rm -f /var/lib/man-db/auto-update
+
 # free up space
 apt-get autoremove -y gcc-12 dpkg-dev gdb build-essential mkvtoolnix iso-codes shared-mime-info rpicam-apps-lite\* || true