Update test/sys/mod.rs with suggestion

Co-authored-by: Alan Somers <[email protected]>

Author: DOhlsson

test/sys/mod.rs

@@ -46,4 +46,5 @@ mod test_ptrace;
 #[cfg(any(target_os = "android", target_os = "linux"))]
 mod test_timerfd;
 #[cfg(target_os = "linux")]
+#[cfg(feature = "process")]
 mod test_prctl;