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

• BLK_BYTECOUNT bsd/include/arpa/ftp.h:128
• BLK_EOF bsd/include/arpa/ftp.h:124
• BLK_EOR bsd/include/arpa/ftp.h:123
• BLK_ERRORS bsd/include/arpa/ftp.h:125
• BLK_RESTART bsd/include/arpa/ftp.h:126
• BREAK bsd/include/arpa/telnet.h:75