Why would you edit a core gzdoom.pk3 file in the first place?
The original approach of the mod did not start out like this. It eventually became this overtime and has been for the last several years with no issues I couldn't fix myself. This topic is about an observation I have made days ago when I pondered why I haven't been seeing the map names in the automap (I had them turned off). Other than this odd glitch, my mod works 100% without issue.
Still, I figured I'd have some explaining to do about my modding antics. I modded GZDoom the same exact way you would make a mod for Quake 3 or Doom 3. By extracting a core file, modifying it, and placing it into a new archive you could effectively modify anything you wanted and still retain the originals. id Software normally designs their games in this fashion so they can patch data files this way.
Keep in mind this was circa 2007 when this was happening. Fast forward into just a few years later (I think around 2010ish). Somewhere down the line of GZDoom's development they have stopped this convenience for me. This was a serious roadblock for me. Since I am of the straggler type, I held out on future releases of GZDoom until one feature was worth converting to the new versions. That feature? Textured automap. I loved that feature from Doom 64. But to have that meant I must make changes to GZDoom.pk3 directly from now on, and just backup the files I wanted to modify.
Now I'm not one to overemphasize on hacks to the code base just to get what I want, but when the changes are minimal itself and still achieve my goal, it comes down to the choice between "do I mod it in myself, or use someone elses' dependancies?"
What mod could be so worth risking the overall integrity of a game's archive, no matter how small? The mod itself has been retitled "The Ultimate Doom 2" for a reason. But to go in depth into details about it would require a new thread about it, and that would be selfish of me. If there's enough curiosity for it I can release it on request.