remove some unneeded imports

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

@@ -273,8 +273,6 @@ pub mod zircon {
 
 #[cfg(target_os = "fuchsia")]
 pub fn futex_wait(futex: &AtomicU32, expected: u32, timeout: Option<Duration>) -> bool {
-    use crate::convert::TryFrom;
-
     // Sleep forever if the timeout is longer than fits in a i64.
     let deadline = timeout
         .and_then(|d| {

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

@@ -7,7 +7,6 @@ mod tests;
 
 use crate::os::unix::prelude::*;
 
-use crate::convert::TryFrom;
 use crate::error::Error as StdError;
 use crate::ffi::{CStr, CString, OsStr, OsString};
 use crate::fmt;

library/std/src/sys/unix/process/process_fuchsia.rs

@@ -166,7 +166,6 @@ impl Process {
     }
 
     pub fn wait(&mut self) -> io::Result<ExitStatus> {
-        use crate::default::Default;
         use crate::sys::process::zircon::*;
 
         let mut proc_info: zx_info_process_t = Default::default();
@@ -199,7 +198,6 @@ impl Process {
     }
 
     pub fn try_wait(&mut self) -> io::Result<Option<ExitStatus>> {
-        use crate::default::Default;
         use crate::sys::process::zircon::*;
 
         let mut proc_info: zx_info_process_t = Default::default();