--- lsys/main.cpp	2008/11/06 14:31:24	1.1
+++ lsys/main.cpp	2018/11/07 12:50:17	1.2
@@ -74,8 +74,8 @@
   ostream *ofile = 0;
   
   char *outfile_str = 0;
-  char *interpreter_str = "turtle";
-  char *interface_str = "gl";
+  const char *interpreter_str = "turtle";
+  const char *interface_str = "gl";
   char *module_str = 0;
   double min, max, step;
   int show_depth = 0;