product:: no crash on load when saved

basegraph.cpp

@@ -1387,6 +1387,7 @@ EX void initgraph() {
   loadConfig();
 #endif
   arcm::current.parse();
+  if(geometry == gProduct) geometry = product::underlying;
 
 #if CAP_COMMANDLINE
   arg::read(2);

config.cpp

@@ -511,6 +511,7 @@ EX void initConfig() {
   addsaver(models::use_atan, "use_atan");
   
   addsaver(arcm::current.symbol, "arcm-symbol", "4^5");
+  addsaverenum(product::underlying, "product-underlying");
   
   for(int i=0; i<isize(ginf); i++) {
     if(ginf[i].flags & qELLIPTIC)