Allow having the type of input argument explicit

Author: nagisa

README.md

@@ -36,7 +36,7 @@ and change the `src/main.rs` to fuzz your code:
 extern crate fuzzer_sys;
 extern crate your_crate;
 
-fuzz_target!(|data| {
+fuzz_target!(|data: &[u8]| {
     // code to fuzz goes here
 });
 ```

src/lib.rs

@@ -22,5 +22,11 @@ macro_rules! fuzz_target {
         pub extern fn rust_fuzzer_test_input($bytes: &[u8]) {
             $body
         }
+    };
+    (|$bytes:ident: &[u8]| $body:block) => {
+        #[no_mangle]
+        pub extern fn rust_fuzzer_test_input($bytes: &[u8]) {
+            $body
+        }
     }
 }