Re: lib/bbitset.h code cleanup for C89

[Akim Demaille]

 Paul> While fixing something else, I noticed that bbitset.h includes
 Paul> limits.h conditionally.  We've been assuming C89 for some time now in
 Paul> the bitset code, so I installed this minor code cleanup.

Paul, actually _you_ have been assuming C89.  I moved Bison to this
implementation of bitsets because it was hosted (at least they were
considering using that one) by the GCC team, so we didn't have to
maintain it by ourselves.  Or at least to share the maintenance.  But
now the sources can no longer be shared :(

At the beginning the changes were ansi2knr'able, but they no longer
are :(