Fix the custom definition of Timespec to implement Copy. (#484)

Author: sunfishcode

src/backend/libc/time/types.rs

@@ -16,7 +16,7 @@ pub type Timespec = c::timespec;
     any(target_arch = "arm", target_arch = "mips", target_arch = "x86"),
     target_env = "gnu",
 ))]
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Copy)]
 #[repr(C)]
 pub struct Timespec {
     /// Seconds.

tests/time/timespec.rs

@@ -6,7 +6,12 @@ fn test_timespec_layout() {
 
     let tv_sec: Secs = 0;
     let tv_nsec: Nsecs = 0;
-    let _ = Timespec { tv_sec, tv_nsec };
+    let x = Timespec { tv_sec, tv_nsec };
+
+    // Test that `Timespec` implements `Copy` and `Debug`.
+    let _y = Timespec { tv_sec, tv_nsec };
+    let _z = Timespec { tv_sec, tv_nsec };
+    dbg!(&x);
 
     #[cfg(not(target_os = "redox"))]
     let _ = Timespec {