aya: fix warnings

aya/src/sys/mod.rs

@@ -9,7 +9,7 @@ mod fake;
 use std::convert::TryInto;
 use std::{ffi::CString, io, mem};
 
-use libc::{c_int, c_long, c_ulong, pid_t, utsname};
+use libc::{c_int, c_long, pid_t, utsname};
 
 pub(crate) use bpf::*;
 #[cfg(test)]

aya/src/sys/perf_event.rs

@@ -1,6 +1,6 @@
 use std::{ffi::CString, mem};
 
-use libc::{c_int, c_ulong, pid_t};
+use libc::{c_int, pid_t};
 
 use crate::generated::{
     perf_event_attr,