Re: ANNOUNCE: DJGPP port of GNU bison 1.33 uploaded

[JT Williams]

In the latest bison (1.33), something has changed with YYDEBUG.
It appears that YYDEBUG is now #define'd (to 0?) when it used to
be left #undef'ed.  Thus, the following block

#ifdef YYDEBUG
...
#endif

was (correctly) skipped in pre-1.33 bison (`bison -d -y foo.y') but
with bison 1.33 this block is now entered (even when debugging support
is not requested).  Changing `#ifdef YYDEBUG' to `#if YYDEBUG' in your
bison .y sources appears to be required user-level adjustment.

(I checked, and the only two .y files in the djgpp distro do not use
YYDEBUG and compile okay with 1.33.)

The YYDEBUG change is Posix-mandated: the bison 1.33 NEWS file reports:

* When the generated parser lacks debugging code, YYDEBUG is now 0
  (as POSIX requires) instead of being undefined.

This entry was made for bison 1.31 (not ported to djgpp).  Due to the
bug in bison 1.32 I continued to use bison 1.30 and so did not encounter
the YYDEBUG snafu.  I have not tried the corrected bison 1.32 port, but
presumably it will now show the same behavior as 1.33.