store_exit_status was clobbering autojump

environment.conf

@@ -20,7 +20,9 @@ show_time() {
 }
 
 # Stores the exit status of the last command for use by show_exit_status function.
-export PROMPT_COMMAND="store_exit_status"
+if [[ ! $PROMPT_COMMAND =~ store_exit_status ]]; then
+  export PROMPT_COMMAND="store_exit_status && ${PROMPT_COMMAND:-:}"
+fi
 store_exit_status() {
   LAST_EXIT_STATUS=$?
 }