Why do I need MC Patcher for this? This tutorial is in the "resrouce packs" subforum, which means that light maps are stored in a normal resource pack, and those can be made manually. There's an actual official way to create resource packs using a specific folder structure. No jar-file modding is needed, so no special tools should be needed.
Old thread is old. I could rename this "An Optifine Tutorial" to be more up to date. Or for that matter, I could just outright update it since much of this isn't exactly accurate anymore.
You need Optifine (or MCPatcher for old versions) because vanilla Minecraft doesn't have this functionality. It specifically works with the mod to produce the effect. Yes, it's added as part of a regular resource pack but it won't show up without the proper mod installed. It's the same as having a resource pack with textures for a mod won't cause the mod's features to magically appear in the game. If it isn't in vanilla MC, having something that works with it won't have any effect unless the corresponding mod is installed.
And if you don't believe me... well... go ahead and try it for yourself! You'll quickly see that you can't get it to work in un-modded Minecraft.