gui: add runonce for is_supported_system with a GUI popup

gui

@@ -83,6 +83,21 @@ runonce <<"EOF"
   fi
 EOF
 
+#run is_supported_system once mostly to check for unsupported ubuntu/debian distros and warn the user with a blocking GUI popup
+runonce <<"EOF"
+  if ! is_supported_system >/dev/null;then
+    text="YOUR SYSTEM IS UNSUPPORTED:
+$(is_supported_system)
+
+Pi-Apps will disable the sending of any error reports until you have resolved the issue above.
+Your mileage may vary with using Pi-Apps in this state. Expect the majority of apps to be broken."
+
+    yadflags=(--class Pi-Apps --name "Pi-Apps" --window-icon="${DIRECTORY}/icons/logo.png" --title="Pi-Apps")
+    userinput_func "$text" "Ok"
+  fi
+  true
+EOF
+
 #Various stuff to run in background (enclosed in brackets so Geany IDE can collapse the code)
 {
 mkdir -p "${DIRECTORY}/data/status" "${DIRECTORY}/data/update-status" \