Handle unknown filename.

src/sbbs3/jsdebug.c

@@ -78,6 +78,8 @@ static void newscript_handler(JSContext  *cx,
 		return;
 	}
 	fname=JS_GetScriptFilename(cx, script);
+	if (fname == NULL)
+		fname = "<unknown>";
 	cs->fname=strdup(fname);
 	if(cs->fname)
 		fname=getfname(fname);