All symbols starting with `l' in 321/solaris

• later 321/solaris/readme.solaris:10
• LOOPBACK 321/solaris/net_udp.c:40
• loopbacks 321/solaris/net_udp.c:56
• loopback_t 321/solaris/net_udp.c:54
• loopmsg_t 321/solaris/net_udp.c:48