update libyuv to hash 5a699df5 from https://chromium.googlesource.com/libyuv/libyuv/

libs/libyuv/unit_test/cpu_thread_test.cc

@@ -0,0 +1,63 @@
+/*
+ *  Copyright 2017 The LibYuv Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS. All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <gtest/gtest.h>
+
+#include "libyuv/cpu_id.h"
+
+#if defined(__clang__)
+#if __has_include(<pthread.h>)
+#define LIBYUV_HAVE_PTHREAD 1
+#endif
+#elif defined(__linux__)
+#define LIBYUV_HAVE_PTHREAD 1
+#endif
+
+#ifdef LIBYUV_HAVE_PTHREAD
+#include <pthread.h>
+#endif
+
+namespace libyuv {
+
+#ifdef LIBYUV_HAVE_PTHREAD
+void* ThreadMain(void* arg) {
+  int* flags = static_cast<int*>(arg);
+
+  *flags = TestCpuFlag(kCpuHasSSSE3);
+  return nullptr;
+}
+#endif  // LIBYUV_HAVE_PTHREAD
+
+// Call TestCpuFlag() from two threads. ThreadSanitizer should not report any
+// data race.
+TEST(LibYUVCpuThreadTest, TestCpuFlagMultipleThreads) {
+#ifdef LIBYUV_HAVE_PTHREAD
+  int cpu_flags1;
+  int cpu_flags2;
+  int ret;
+  pthread_t thread1;
+  pthread_t thread2;
+
+  MaskCpuFlags(0);  // Reset to 0 to allow auto detect.
+  ret = pthread_create(&thread1, nullptr, ThreadMain, &cpu_flags1);
+  ASSERT_EQ(ret, 0);
+  ret = pthread_create(&thread2, nullptr, ThreadMain, &cpu_flags2);
+  ASSERT_EQ(ret, 0);
+  ret = pthread_join(thread1, nullptr);
+  EXPECT_EQ(ret, 0);
+  ret = pthread_join(thread2, nullptr);
+  EXPECT_EQ(ret, 0);
+  EXPECT_EQ(cpu_flags1, cpu_flags2);
+#else
+  printf("pthread unavailable; Test skipped.");
+#endif  // LIBYUV_HAVE_PTHREAD
+}
+
+}  // namespace libyuv