rdma: port the hipObject v2 RC session core

Port the hipObject v2 reliable-connection session core into
cuwrapper/rc: the session table and state machine, the wire
codec for the hipobj-rc-v2 headers, request parsing, the
injectable clock and randomness sources, the transport layer
(QP/CQ lifecycle, RTR/RTS transitions, staging registration),
the data phase (RDMA write with immediate for GET, receive with
immediate for PUT), the RDMA token codec, and the dynamically
loaded ibverbs shim (ibv-core.h plus the dlopen host binding).

The sources are a port of the upstream hipObject v2 core, kept
close to the original so the two trees can be diffed during
review. Nothing links against them yet; a Makefile rule builds
the objects into rdma/librcserver.a for the ABI layer that
follows.

Signed-off-by: Jihyeon Gim <potatogim@potatogim.net>

cuwrapper/rc/v2-clock.cpp

@@ -0,0 +1,41 @@
+/* Copyright (c) Advanced Micro Devices, Inc. All rights reserved.
+ * Copyright (c) Gluesys Inc. and Jihyeon Gim. All rights reserved.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "v2-clock.h"
+
+#include <chrono>
+
+namespace hipObj {
+namespace v2 {
+
+namespace {
+
+class SteadyClock : public ClockSource {
+public:
+  uint64_t nowMs() override {
+    auto now = std::chrono::steady_clock::now().time_since_epoch();
+    return static_cast<uint64_t>(
+      std::chrono::duration_cast<std::chrono::milliseconds>(now).count());
+  }
+};
+
+SteadyClock g_defaultClock;
+ClockSource* g_override = nullptr;
+
+} // namespace
+
+ClockSource& clockSource() {
+  return g_override ? *g_override : static_cast<ClockSource&>(g_defaultClock);
+}
+
+ClockSource* setClockSourceForTest(ClockSource* source) {
+  ClockSource* previous = g_override;
+  g_override = source;
+  return previous;
+}
+
+} // namespace v2
+} // namespace hipObj