remove pic->native_stack_start

src/main.c

@@ -19,9 +19,12 @@ int picrin_argc;
 char **picrin_argv;
 char **picrin_envp;
 
+extern char *picrin_native_stack_start; /* for call/cc */
+
 int
 main(int argc, char *argv[], char **envp)
 {
+  char t;
   pic_state *pic;
   int status;
 
@@ -31,6 +34,8 @@ main(int argc, char *argv[], char **envp)
   picrin_argv = argv;
   picrin_envp = envp;
 
+  picrin_native_stack_start = &t;
+
   pic_try {
     pic_init_picrin(pic);