Allow deprecations in macros so we don't give everyone warnings

The deprecations will be fixed later by raising the minimum supported
Rust version for this crate. These deprecations take effect in Rust 1.34
and were enabled in rust-lang/rust#57425.

src/macros.rs

@@ -15,6 +15,7 @@ let cls = class!(NSObject);
 #[macro_export]
 macro_rules! class {
     ($name:ident) => ({
+        #[allow(deprecated)]
         #[inline(always)]
         fn get_class(name: &str) -> Option<&'static $crate::runtime::Class> {
             unsafe {
@@ -44,6 +45,7 @@ macro_rules! sel_impl {
     // Declare a function to hide unsafety, otherwise we can trigger the
     // unused_unsafe lint; see rust-lang/rust#8472
     ($name:expr) => ({
+        #[allow(deprecated)]
         #[inline(always)]
         fn register_sel(name: &str) -> $crate::runtime::Sel {
             unsafe {