cleanup: remove unused attributes; add `dev` compile feature that'll run clippy

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 
 name = "secp256k1"
-version = "0.5.2"
+version = "0.5.3"
 authors = [ "Dawid Ciężarkiewicz <dpc@ucore.info>",
             "Andrew Poelstra <apoelstra@wpsoftware.net>" ]
 license = "CC0-1.0"
@@ -22,9 +22,12 @@ path = "src/lib.rs"
 
 [features]
 unstable = []
+default = []
+dev = ["clippy"]
 
 [dependencies]
 arrayvec = "0.3"
+clippy = {version = "0.0", optional = true}
 rand = "0.3"
 libc = "0.1"
 rustc-serialize = "0.3"

src/ffi.rs

@@ -67,14 +67,12 @@ impl PublicKey {
 
 /// Library-internal representation of a Secp256k1 signature
 #[repr(C)]
-#[allow(raw_pointer_derive)]
 pub struct Signature([c_uchar; 64]);
 impl_array_newtype!(Signature, c_uchar, 64);
 impl_raw_debug!(Signature);
 
 /// Library-internal representation of a Secp256k1 signature + recovery ID
 #[repr(C)]
-#[allow(raw_pointer_derive)]
 pub struct RecoverableSignature([c_uchar; 65]);
 impl_array_newtype!(RecoverableSignature, c_uchar, 65);
 impl_raw_debug!(RecoverableSignature);
@@ -95,7 +93,6 @@ impl RecoverableSignature {
 
 /// Library-internal representation of an ECDH shared secret
 #[repr(C)]
-#[allow(raw_pointer_derive)]
 pub struct SharedSecret([c_uchar; 32]);
 impl_array_newtype!(SharedSecret, c_uchar, 32);
 impl_raw_debug!(SharedSecret);

src/lib.rs

@@ -32,6 +32,10 @@
 #![deny(unused_mut)]
 #![warn(missing_docs)]
 
+#![cfg_attr(feature = "dev", allow(unstable_features))]
+#![cfg_attr(feature = "dev", feature(plugin))]
+#![cfg_attr(feature = "dev", plugin(clippy))]
+
 #![cfg_attr(all(test, feature = "unstable"), feature(test))]
 #[cfg(all(test, feature = "unstable"))] extern crate test;