Deprecated calling sims without a core argument

piton/tools/src/sims/sims,2.0

@@ -349,8 +349,8 @@ die ("DIE. -pico and -pico_het cannot both be set") if ($opt{pico} && $opt{pico_
 
 # Setting ost1 by default. This works better than default to 1
 # for heterogeneous-ISA stuff
-if (!$opt{pico} && !$opt{ariane}) {
-  $opt{ost1} = 1 ;
+if ((!$opt{pico} && !$opt{ariane} && !$opt{ost1}) && ($opt{sys} eq "manycore")) {
+  die ("DIE. Calling sims without specifying a core is no longer supported (you probably want to add -ariane, -ost1, or similar to your sims command)") ;
 }
 
 push (@{$opt{config_cpp_args}}, "-DFLIST_OST1")     if ($opt{ost1} || $opt{pico_het}) ;