libbinder: build on Trusty

Adds a new trusty/ subdirectory containing all the files
needed to build Binder RPC on Trusty, including:
* A RpcServerTrusty class used to create Trusty Binder services
* The underlying RpcTransportTipcTrusty transport that interfaces
  between libbinder and TIPC
* Trusty implementations of some OS-specific functionality, like logging
* Make-based build file for libbinder in the Trusty build system

Bug: 224644083
Test: build Trusty
Change-Id: I25b97736d41489d20c2dd266e8e110764215378c
diff --git a/libs/binder/RpcServer.cpp b/libs/binder/RpcServer.cpp
index 096d5cc..49be4dd 100644
--- a/libs/binder/RpcServer.cpp
+++ b/libs/binder/RpcServer.cpp
@@ -209,9 +209,10 @@
 
         {
             RpcMutexLockGuard _l(mLock);
-            RpcMaybeThread thread = RpcMaybeThread(&RpcServer::establishConnection,
-                                                   sp<RpcServer>::fromExisting(this),
-                                                   std::move(clientFd), addr, addrLen);
+            RpcMaybeThread thread =
+                    RpcMaybeThread(&RpcServer::establishConnection,
+                                   sp<RpcServer>::fromExisting(this), std::move(clientFd), addr,
+                                   addrLen, RpcSession::join);
 
             auto& threadRef = mConnectingThreads[thread.get_id()];
             threadRef = std::move(thread);
@@ -294,8 +295,10 @@
     return mConnectingThreads.size();
 }
 
-void RpcServer::establishConnection(sp<RpcServer>&& server, base::unique_fd clientFd,
-                                    std::array<uint8_t, kRpcAddressSize> addr, size_t addrLen) {
+void RpcServer::establishConnection(
+        sp<RpcServer>&& server, base::unique_fd clientFd, std::array<uint8_t, kRpcAddressSize> addr,
+        size_t addrLen,
+        std::function<void(sp<RpcSession>&&, RpcSession::PreJoinSetupResult&&)>&& joinFn) {
     // mShutdownTrigger can only be cleared once connection threads have joined.
     // It must be set before this thread is started
     LOG_ALWAYS_FATAL_IF(server->mShutdownTrigger == nullptr);
@@ -478,7 +481,7 @@
     // avoid strong cycle
     server = nullptr;
 
-    RpcSession::join(std::move(session), std::move(setupResult));
+    joinFn(std::move(session), std::move(setupResult));
 }
 
 status_t RpcServer::setupSocketServer(const RpcSocketAddress& addr) {