libbinder_rs: Add libbinder_rs_on_trusty_mock

Build a mock version of Trusty libbinder_rs
on Android for build testing purposes.

Bug: 242243245
Test: m libbinder_rs_on_trusty_mock
Change-Id: I1b61550af6fbbeac68903c41b5bd20729973b066
diff --git a/libs/binder/rust/src/lib.rs b/libs/binder/rust/src/lib.rs
index 0540ed3..0f9c58c 100644
--- a/libs/binder/rust/src/lib.rs
+++ b/libs/binder/rust/src/lib.rs
@@ -100,9 +100,9 @@
 mod native;
 mod parcel;
 mod proxy;
-#[cfg(not(target_os = "trusty"))]
+#[cfg(not(trusty))]
 mod service;
-#[cfg(not(target_os = "trusty"))]
+#[cfg(not(trusty))]
 mod state;
 
 use binder_ndk_sys as sys;
@@ -112,13 +112,13 @@
 pub use error::{ExceptionCode, IntoBinderResult, Status, StatusCode};
 pub use parcel::{ParcelFileDescriptor, Parcelable, ParcelableHolder};
 pub use proxy::{DeathRecipient, SpIBinder, WpIBinder};
-#[cfg(not(target_os = "trusty"))]
+#[cfg(not(trusty))]
 pub use service::{
     add_service, force_lazy_services_persist, get_declared_instances, get_interface, get_service,
     is_declared, is_handling_transaction, register_lazy_service, wait_for_interface,
     wait_for_service, LazyServiceGuard,
 };
-#[cfg(not(target_os = "trusty"))]
+#[cfg(not(trusty))]
 pub use state::{ProcessState, ThreadState};
 
 /// Binder result containing a [`Status`] on error.