Add struct linger

src/header/sys_socket/mod.rs

@@ -12,6 +12,13 @@ pub mod constants;
 pub type sa_family_t = u16;
 pub type socklen_t = u32;
 
+#[repr(C)]
+#[derive(Default)]
+pub struct linger {
+    pub l_onoff: c_int,
+    pub l_linger: c_int,
+}
+
 #[repr(C)]
 pub struct msghdr {
     pub msg_name: *mut c_void,