Add addrinfo constants

src/header/netdb/mod.rs

@@ -96,6 +96,27 @@ pub struct addrinfo {
     ai_next: *mut addrinfo,    /* next structure in linked list */
 }
 
+pub const AI_PASSIVE: c_int = 0x0001;
+pub const AI_CANONNAME: c_int = 0x0002;
+pub const AI_NUMERICHOST: c_int = 0x0004;
+pub const AI_V4MAPPED: c_int = 0x0008;
+pub const AI_ALL: c_int = 0x0010;
+pub const AI_ADDRCONFIG: c_int = 0x0020;
+pub const AI_NUMERICSERV: c_int = 0x0400;
+
+pub const EAI_BADFLAGS: c_int = -1;
+pub const EAI_NONAME: c_int = -2;
+pub const EAI_AGAIN: c_int = -3;
+pub const EAI_FAIL: c_int = -4;
+pub const EAI_NODATA: c_int = -5;
+pub const EAI_FAMILY: c_int = -6;
+pub const EAI_SOCKTYPE: c_int = -7;
+pub const EAI_SERVICE: c_int = -8;
+pub const EAI_ADDRFAMILY: c_int = -9;
+pub const EAI_MEMORY: c_int = -10;
+pub const EAI_SYSTEM: c_int = -11;
+pub const EAI_OVERFLOW: c_int = -12;
+
 static mut NETDB: c_int = 0;
 static mut NET_ENTRY: netent = netent {
     n_name: ptr::null_mut(),