Update Changelog.md

Previous implementation didn't crash because `closedir(...)` is lenient.

Changelog.md

@@ -4,6 +4,8 @@
 
 Fix internal erronous buffer declaration.
 
+Fix internal missing NULL check.
+
 ## Version 1.2
 
 Add the `--generate-dir=<DIR>` option, which will generate all html into the

src/arg_parse.c

@@ -184,7 +184,9 @@ Args parse_args(int32_t argc, char **argv) {
       } else {
         printf("Directory \"%s\" exists.\n", args.generate_dir);
       }
-      closedir(d);
+      if (d) {
+        closedir(d);
+      }
     } else if (strcmp(argv[0], "--generate-enable-overwrite") == 0) {
       args.flags |= 4;
     } else {