add missing TCP socket options for illumos

The socket2 crate now depends on TCP_MAXSEG, and the rest of the options
may as well come along for the ride.

src/unix/solarish/illumos.rs

@@ -25,6 +25,7 @@ pub const EFD_CLOEXEC: ::c_int = 0x80000;
 pub const TCP_KEEPIDLE: ::c_int = 34;
 pub const TCP_KEEPCNT: ::c_int = 35;
 pub const TCP_KEEPINTVL: ::c_int = 36;
+pub const TCP_CONGESTION: ::c_int = 37;
 
 extern "C" {
     pub fn eventfd(init: ::c_uint, flags: ::c_int) -> ::c_int;

src/unix/solarish/mod.rs

@@ -1385,7 +1385,24 @@ pub const IP_DROP_MEMBERSHIP: ::c_int = 20;
 pub const IPV6_JOIN_GROUP: ::c_int = 9;
 pub const IPV6_LEAVE_GROUP: ::c_int = 10;
 
-pub const TCP_NODELAY: ::c_int = 1;
+// These TCP socket options are common between illumos and Solaris, while higher
+// numbers have generally diverged:
+pub const TCP_NODELAY: ::c_int = 0x1;
+pub const TCP_MAXSEG: ::c_int = 0x2;
+pub const TCP_KEEPALIVE: ::c_int = 0x8;
+pub const TCP_NOTIFY_THRESHOLD: ::c_int = 0x10;
+pub const TCP_ABORT_THRESHOLD: ::c_int = 0x11;
+pub const TCP_CONN_NOTIFY_THRESHOLD: ::c_int = 0x12;
+pub const TCP_CONN_ABORT_THRESHOLD: ::c_int = 0x13;
+pub const TCP_RECVDSTADDR: ::c_int = 0x14;
+pub const TCP_INIT_CWND: ::c_int = 0x15;
+pub const TCP_KEEPALIVE_THRESHOLD: ::c_int = 0x16;
+pub const TCP_KEEPALIVE_ABORT_THRESHOLD: ::c_int = 0x17;
+pub const TCP_CORK: ::c_int = 0x18;
+pub const TCP_RTO_INITIAL: ::c_int = 0x19;
+pub const TCP_RTO_MIN: ::c_int = 0x1a;
+pub const TCP_RTO_MAX: ::c_int = 0x1b;
+pub const TCP_LINGER2: ::c_int = 0x1c;
 
 pub const SOL_SOCKET: ::c_int = 0xffff;
 pub const SO_DEBUG: ::c_int = 0x01;