makedist: warn user to run make neddoc if not already done

Author: avarga

releng/makedist

@@ -28,6 +28,8 @@ git checkout-index -a -f --prefix=$SIMU5G_ROOT/out/$DIRNAME/ || { echo --- error
 
 echo "simu5g-$BUILDID" > $SIMU5G_ROOT/out/$DIRNAME/Version_build
 
+echo 'ATTENTION! doc/neddoc/ must contain freshly generated content, type "make neddoc" and re-run "makedist" if it does not'
+
 echo Creating $FILENAME_DOC.
 # switch to doc dir
 cd $SIMU5G_ROOT/doc