Defines starting with `s' in ufs

• SBLOCK ufs/fs.h:69
• SBOFF ufs/fs.h:67
• SBSIZE ufs/fs.h:65
• SELF ufs/ufs_lockf.c:154
• SINGLE ufs/ufs_inode.c:395
• SUBCMDMASK ufs/quota.h:84
• SUBCMDSHIFT ufs/quota.h:85