Remove extra trait, clean up cfg statements

src/hyperfine/timer/mod.rs

@@ -2,25 +2,16 @@ mod internal;
 
 pub mod wallclocktimer;
 
-#[cfg(not(windows))]
-mod unix_timer;
-
-#[cfg(not(windows))]
-pub use self::unix_timer::get_cpu_timer;
-
-#[cfg(windows)]
-mod windows_timer;
-
-#[cfg(windows)]
-pub use self::windows_timer::get_cpu_timer;
-
-use std::process::Child;
-
-pub trait Timer
-where
-    Self: TimerStart + TimerStop,
-{
+cfg_if! {
+    if #[cfg(windows)] {
+        mod windows_timer;
+        pub use self::windows_timer::get_cpu_timer;
+    } else {
+        mod unix_timer;
+        pub use self::unix_timer::get_cpu_timer;
+    }
 }
+use std::process::Child;
 
 /// Defines start functionality of a timer.
 pub trait TimerStart {

src/main.rs

@@ -1,15 +1,21 @@
 extern crate atty;
+
+#[macro_use]
+extern crate cfg_if;
+
 #[macro_use]
 extern crate clap;
 extern crate colored;
 extern crate indicatif;
 extern crate statistical;
 
-#[cfg(not(windows))]
-extern crate libc;
-
-#[cfg(windows)]
-extern crate winapi;
+cfg_if! {
+    if #[cfg(windows)] {
+        extern crate winapi;
+    } else {
+        extern crate libc;
+    }
+}
 
 #[cfg(test)]
 #[macro_use]