drop bison 1.x?

Hi, It would help a lot to test the parser if we drop bison 1.x support. It won't change anything in the parser rules or in the code base but only the way we test it. Bison version 1.x has different messages than 2.x (formats and contents). It causes some tests to fail because of these different messages. I wonder if we could simply stop to support bison 1.x in 5.3 and later or at least in 5.4+. But if we do it in 5.4+ only it will be harder to maintain both tests synced and compared the results between the two branches (eventual BC breaks or similar breakages). Comments? Cheers, -- Pierre @pierrejoye | http://blog.thepimp.net | http://www.libgd.org