External drive option

src/freedombone-image-make

 # Packages needed for self-hosted development
 dev_pkgs="build-essential devscripts make man-db emacs org-mode git mercurial"
 
-echo Building "$MACHINE" "$PROJECT_NAME" for "$ARCHITECTURE".
+echo Building "$MACHINE" "$PROJECT_NAME" for "$ARCHITECTURE" "$EXTERNAL_DRIVE"
 
 case "$MACHINE" in
     beaglebone)
      ARCHITECTURE="$ARCHITECTURE" \
      SOURCE="$SOURCE" \
      CUSTOM_SETUP="$CUSTOM_SETUP" \
+     EXTERNAL_DRIVE="$EXTERNAL_DRIVE" \
      $VMDEBOOTSTRAP \
      --log "$(dirname "$IMAGE")/${PROJECT_NAME}.log" \
      --log-level debug \