How many nested #if(n)defs?

I have a header file that uses a handful of nested #ifndef statements to determine whether or not debug support should be included.
Like this:

#define DEBUG 1
#ifndef DEBUG_THIS
 #ifndef DEBUG_THAT
  #ifndef DEBUG_THEOTHER
   #undef DEBUG
  #endif
 #endif
#endif

So ‘DEBUG’ will be defined (as ‘1’ but that’s immaterial) so long as at least one of the other debug options are defined.

Does anybody know what the limit for nested if(n)def statements is? I just threw together a contrived test, and the compiler had no problems with 50 of them.

Update: Okay, for the lulz I did a test for #ifndef A0 through A9, then copypasted it so there were one thousand and two hundred nested conditionals. Didn’t faze CC one bit. Didn’t appear to noticably slow the compiler down, either.

I deleted one #endif and the compiler threw errors, so it is chundering through that lot and not just block-optimising it out (despite the painfully obvious repetition).

Is there a limit? Or can it keep going until memory runs out?

I give up.

Time to perform a full build of my project with the following (1.4MiB of unique definitions) is 31s.
Time to do a full build without them? 18 seconds. So processing 65 thousand randomly generated definitions seven times (as there are seven source files built) adds a mere 13s.
Wow. And wow again.

I think we can safely say that for all intensive porpoises, there is no limit.

f% = OPENOUT("RAM:$.ifdefs")
FOR l% = 1 TO 65536
  n$ = "#ifndef "
  FOR r% = 1 TO RND(10)
    n$ = n$ + CHR$(RND(26)+64)
  NEXT
  BPUT#f%, n$
NEXT
BPUT#f%, "#define OH_MY_GOD 1"
FOR l% = 1 TO 65536
  BPUT#f%, "#endif"
NEXT
CLOSE#f%
OSCLI("SetType RAM:$.ifdefs &FFF")
END