Bison vs. const vs. AIX

[Kaveh R. Ghazi]

 > From: Mark Mitchell <mark@codesourcery.com>
 > 
 > On AIX, using `cc' to bootstrap doesn't work.  The reason is that in
 > that `cc' supports `const', but doesn't define __STDC__.  So, all of
 > our headers use `const', but in c-parse.c, Bison does:
 > 
 >   #ifndef __cplusplus
 >   #ifndef __STDC__
 >   #define const
 >   #endif
 >   #endif
 > 
 > Then, we get const-mismatches in the body of c-parse.c.
 > 
 > I don't see a generic way to fix this problem.  I was going to
 > duplicate the Bison logic in system.h, but that fails if the compiler
 > rejects multiple definitions of the same macro, which some compilers
 > do.  (Note that Bison is not polite enough to have wrapped its
 > definition in `#ifndef const'.)
 > 
 > Does anyone see a way to fix this problem?  Otherwise, we need to
 > force the bootstrap compiler to be `xlc', rather than `cc', on AIX.

The true switch used in the rest of gcc is ANSI_PROTOTYPES defined in
ansidecl.h.  That macro is set when __STDC__, _AIX (causing this
problem), and other special cases.  What we need to do to get bison on
board is to tell it we are __STDC__ when ANSI_PROTOTYPES is defined.
How about putting the following code in the file?

  /* Warning!  Gross hack alert.  <Explanation...>  */
  #if defined(ANSI_PROTOTYPES) && !defined(__STDC__)
  #define __STDC__
  #endif

You should probably try putting it in just after c_parse_init() so it
gets done just above the bison inserted const define.

		--Kaveh
--
Kaveh R. Ghazi			Engagement Manager / Project Services
ghazi@caip.rutgers.edu		Qwest Internet Solutions