Is your feature request related to a problem? Please describe.
If you disable the "Create enum declarations" option in UndertaleModTool (creating the issue here since it's directly related to the (de)compiler), decompiled code will still have enums (both UnknownEnum and game-specific enums) in it, but compiling said code will not compile the enums since they're not in the GML text. It will instead compile a regular variable access, which will crash the game.
Describe the solution you'd like
Make game-specific enums and UnknownEnum count anyways, even if they're not present in the code. Maybe defining an enum would cause it to overwrite the existing one with that name.
Describe alternatives you've considered
The other option is making the option disable enums in the decompiler too but I don't want that.