Akim Demaille authored Mar 19, 2012 and Alexandre Duret-Lutz committed May 22, 2012

* lib/src/krat_exp/krat_exp_bison.yy: Require Bison 2.5.
Require locations, for upward compatibility with 2.6.
Use a couple typedefs for clarity.
Factor vcsnyy::... with a namespace vcsnyy {...}.
Use code requires/provides for clarity.