I think I also found the issue with nested ifdef's because of you :D
When it finds a if or ifdef with a false condition, it then proceeds to skip all data until the next #endif
But, that also means it skips if's and ifdefs, causing it to misscount the #endif

So in terms of hierarchy, instead of

#if 
  #ifdef
    #endif (return back one level)
  #endif (return back one level)

it does

#if
  #ifdef (skip)
  #endif (return back one level)
(#if ended)
#endif (uh.. what.. eh. uh.. ok.. back one level but we are in root so.. file just ends here)

Always a pleasure to give you weird bugs to fix <3

Thanks!

And me?

You too ;D