Remove unnecessary extern C function

src/start.rs

@@ -53,7 +53,6 @@ pub unsafe extern "C" fn relibc_start(sp: &'static Stack) -> ! {
         static __init_array_start: extern "C" fn();
         static __init_array_end: extern "C" fn();
 
-        fn pthread_init() -> c_int;
         fn _init();
         fn main(argc: isize, argv: *mut *mut c_char, envp: *mut *mut c_char) -> c_int;
     }