refactor(lib): remove build script features since minimum version is higher

src/common/macros.rs

@@ -1,21 +0,0 @@
-#[macro_export]
-#[cfg(__hyper_impl_trait_available)]
-macro_rules! impl_trait {
-    (ty: $($t:tt)+) => {
-        impl $($t)+
-    };
-    (e: $e:expr) => {
-        $e
-    }
-}
-
-#[macro_export]
-#[cfg(not(__hyper_impl_trait_available))]
-macro_rules! impl_trait {
-    (ty: $($t:tt)+) => {
-        Box<$($t)+>
-    };
-    (e: $e:expr) => {
-        Box::new($e)
-    }
-}

src/common/mod.rs

@@ -3,8 +3,6 @@ pub(crate) mod drain;
 mod exec;
 pub(crate) mod io;
 mod lazy;
-#[macro_use]
-mod macros;
 mod never;
 
 pub(crate) use self::buf::StaticBuf;