Traditionally, patch -b would produce a backup file with suffix .orig. According to the patch-2.5.4-4 man page, this is still true. However, /usr/bin/patch (as shipped in RH7) instead uses an ugly unnumbered "~" suffix; i.e. foo's backup file is foo~ not foo.orig. This occurs on an ext2 file system, so the name length rule doesn't apply. And no, I don't have SIMPLE_BACKUP_SUFFIX set in my environment. As someone who has been doing a _lot_ of diff and patch the last 12+ years, I find this change extremely distasteful.
Indeed. Fixed in patch-2.5.4-7, which should show up in Rawhide next time it's generated.