LibC: Stub out wcsnrtombs

Author: https://github.com/BertalanD
Commit: 54eee525e6
Pull-request: https://github.com/SerenityOS/serenity/pull/9378
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/itamar8910
Reviewed-by: https://github.com/linusg ✅
Reviewed-by: https://github.com/nico
Reviewed-by: https://github.com/timschumi

Userland/Libraries/LibC/wchar.cpp

@@ -550,4 +550,10 @@ int wmemcmp(const wchar_t* s1, const wchar_t* s2, size_t n)
     }
     return 0;
 }
+
+size_t wcsnrtombs(char*, const wchar_t**, size_t, size_t, mbstate_t*)
+{
+    dbgln("FIXME: Implement wcsnrtombs()");
+    TODO();
+}
 }