clean up `c::linger` conversion

library/std/src/sys/unix/net.rs

@@ -387,7 +387,7 @@ pub fn shutdown(&self, how: Shutdown) -> io::Result<()> {
     pub fn set_linger(&self, linger: Option<Duration>) -> io::Result<()> {
         let linger = libc::linger {
             l_onoff: linger.is_some() as libc::c_int,
-            l_linger: linger.map(|dur| dur.as_secs() as libc::c_int).unwrap_or_default(),
+            l_linger: linger.unwrap_or_default().as_secs() as libc::c_int,
         };
 
         setsockopt(self, libc::SOL_SOCKET, SO_LINGER, linger)

library/std/src/sys/windows/net.rs

@@ -449,7 +449,7 @@ pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
     pub fn set_linger(&self, linger: Option<Duration>) -> io::Result<()> {
         let linger = c::linger {
             l_onoff: linger.is_some() as c_ushort,
-            l_linger: linger.map(|dur| dur.as_secs() as c_ushort).unwrap_or_default(),
+            l_linger: linger.unwrap_or_default().as_secs() as c_ushort,
         };
 
         net::setsockopt(self, c::SOL_SOCKET, c::SO_LINGER, linger)