Defines starting with `d' in nfs

• DIRHDSIZ nfs/nfs_vnops.c:239
• DRT_CACHEDROP nfs/nfsrtt.h:80
• DRT_CACHEREPLY nfs/nfsrtt.h:79
• DRT_NQNFS nfs/nfsrtt.h:77
• DRT_TCP nfs/nfsrtt.h:78