Patch for issue 845 and 828 

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4686 0b2b3880-5936-4365-a048-eb17d2e5a6bf
fix issue 828 and 845

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4687 0b2b3880-5936-4365-a048-eb17d2e5a6bf
Again on issue 845 and 828

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4688 0b2b3880-5936-4365-a048-eb17d2e5a6bf
Fix bug 845 & 826: errno !=0 and not only errno==ERANGE

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4689 0b2b3880-5936-4365-a048-eb17d2e5a6bf
Accepted fix for bug  845 & 826

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4690 0b2b3880-5936-4365-a048-eb17d2e5a6bf