keep networking packages for containers

Author: yodaaut

.build/images/dietpi-installer

@@ -863,6 +863,22 @@ setenv rootuuid "true"' /boot/boot.cmd
 		G_DIETPI-NOTIFY 2 'Marking all packages as auto-installed first, to allow effective autoremove afterwards'
 		local apackages
 		mapfile -t apackages < <(apt-mark showmanual)
+
+		# Containers: keep necessary packages to avoid losing network connectivity
+		if [[ ${apackages[0]} && $G_HW_MODEL == 75 ]]
+		then
+			rpackages=(
+				'ifupdown'
+				'isc-dhcp-client'
+			)
+			apackages_string="${apackages[*]}"
+			for pkg in "${apackages[@]}"
+			do
+				apackages_string=$(echo "$apackages_string" | sed "s/\b$pkg\b//g" | tr -s ' ')
+			done
+			IFS=' ' read -r -a apackages <<< "$apackages_string"
+		fi
+
 		[[ ${apackages[0]} ]] && G_EXEC apt-mark auto "${apackages[@]}"
 		unset -v apackages