Defines starting with `d' in nfs

• DIRHDSIZ nfs/nfs_vnops.c:252
• DRT_CACHEDROP nfs/nfsrtt.h:84
• DRT_CACHEREPLY nfs/nfsrtt.h:83
• DRT_NFSV3 nfs/nfsrtt.h:85
• DRT_NQNFS nfs/nfsrtt.h:81
• DRT_TCP nfs/nfsrtt.h:82