--- test_eng/Testout.pm
+++ test_eng/Testout.pm
@@ -45,6 +45,11 @@ $DEFAULT = undef;
 
 if ($file =~ /plot|graph|all/) {
   if ($ENV{MP_NOGNUPLOT}) {
+    @not_yet_defined{qw(
+      plotbox plotcolor plotcursor plotdraw ploth plothraw plotinit plotlines
+      plotmove plotpoints plotrline plotrmove plotrpoint psdraw psploth
+      psplothraw plotscale plotkill
+    )} = (1) x 10000;
     $skip_gnuplot = 1;
   } else {
     eval { link_gnuplot() };