Defines starting with `s' in ufs

• SBLOCK ufs/fs.h:65
• SBOFF ufs/fs.h:63
• SBSIZE ufs/fs.h:61
• SELF ufs/ufs_lockf.c:63
• SINGLE ufs/ufs_inode.c:383
• SUBCMDMASK ufs/quota.h:83
• SUBCMDSHIFT ufs/quota.h:84