> What version of bison are you using? Perhaps a newer version would fix
> this problem.
PC with gcc 3.2 bison 1.875 works not
Solaris bison 1.875 works not
PC with gcc 2.95.3 bison 1.35 works
As I can see 1.875 is the latest bison version at http://www.gnu.org.
Meanwhile a solution is uncommenting the
> __attribute__ ((__unused__))