PR 4260 notes that the yacc output has problems on platforms that do not
have ANSI C realloc(3), and thus crash on realloc(NULL, x). I don't
personally care about those systems, and would like to close the PR with
a message saying that these systems are too old to be supported. OTOH, we
do the #if __STDC__ song and dance regarding prototypes etc., so we are
trying to work on at least some non-ANSI systems...

So what is the "correct" thing to do?

   /Krister