Defines starting with `b' in bsd/include/arpa

• BLK_BYTECOUNT bsd/include/arpa/ftp.h:131
• BLK_EOF bsd/include/arpa/ftp.h:127
• BLK_EOR bsd/include/arpa/ftp.h:126
• BLK_ERRORS bsd/include/arpa/ftp.h:128
• BLK_RESTART bsd/include/arpa/ftp.h:129
• BREAK bsd/include/arpa/telnet.h:78