initial fix for #99 (issue w/script:name when not running a script; will now report "<none>" instead of garbage)

FossilOrigin-Name: 003f7b2e0650a004cc264cafdb29c5634a32d260cb137a08835a982557e0e48e

RELEASE-NOTES

@@ -51,6 +51,8 @@
   - formatting cleanups
   - added ioctl device
   - new "-p" option to run non-Unu format source files
+  - now report "<none>" for `script:name` if no file is being
+    run
 
 Future Notes
 

vm/nga-c/retro.c

@@ -563,6 +563,9 @@ V scripting_include_plain(NgaState *vm) {
 }
 
 V scripting_name(NgaState *vm) {
+  if ((vm->sys_argc - 2) <= 0)
+    stack_push(vm, string_inject(vm, "<none>", stack_pop(vm)));
+  else
     stack_push(vm, string_inject(vm, vm->sys_argv[1], stack_pop(vm)));
 }
 
@@ -1123,6 +1126,9 @@ int main(int argc, char **argv) {
   vm->sys_argc = argc;           /* Point the global argc and */
   vm->sys_argv = argv;           /* argv to the actual ones   */
 
+  strlcpy(vm->scripting_sources[0], "<none>", 8192);
+
+
   /* Check arguments. If no flags were passed, load & run the
      file specified and exit. */
   if (argc >= 2 && argv[1][0] != '-') {