LAA flag under Mingw

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@7425 8aca7d54-2c30-db11-9de9-000461428c89
Revert last commit

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@7426 8aca7d54-2c30-db11-9de9-000461428c89