Add _android files for building DartVM on Android

runtime/platform/thread_android.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/thread.h"
 
 #include <errno.h>
 #include <sys/time.h>
 
 #include "platform/assert.h"
@@ skipping 193 matching lines @@
   result = pthread_mutex_init(data_.mutex(), &mutex_attr);
   VALIDATE_PTHREAD_RESULT(result);
 
   result = pthread_mutexattr_destroy(&mutex_attr);
   VALIDATE_PTHREAD_RESULT(result);
 
   pthread_condattr_t cond_attr;
   result = pthread_condattr_init(&cond_attr);
   VALIDATE_PTHREAD_RESULT(result);
 
-  result = pthread_condattr_setclock(&cond_attr, CLOCK_MONOTONIC);
-  VALIDATE_PTHREAD_RESULT(result);
-
   result = pthread_cond_init(data_.cond(), &cond_attr);
   VALIDATE_PTHREAD_RESULT(result);
 
   result = pthread_condattr_destroy(&cond_attr);
   VALIDATE_PTHREAD_RESULT(result);
 }
 
 
 Monitor::~Monitor() {
   int result = pthread_mutex_destroy(data_.mutex());
@@ skipping 21 matching lines @@
 Monitor::WaitResult Monitor::Wait(int64_t millis) {
   // TODO(iposva): Do we need to track lock owners?
   Monitor::WaitResult retval = kNotified;
   if (millis == 0) {
     // Wait forever.
     int result = pthread_cond_wait(data_.cond(), data_.mutex());
     VALIDATE_PTHREAD_RESULT(result);
   } else {
     struct timespec ts;
     ComputeTimeSpec(&ts, millis);
-    int result = pthread_cond_timedwait(data_.cond(), data_.mutex(), &ts);
+    int result = pthread_cond_timedwait_monotonic(
+        data_.cond(), data_.mutex(), &ts);
     ASSERT((result == 0) || (result == ETIMEDOUT));
     if (result == ETIMEDOUT) {
       retval = kTimedOut;
     }
   }
   return retval;
 }
 
 
 void Monitor::Notify() {
   // TODO(iposva): Do we need to track lock owners?
   int result = pthread_cond_signal(data_.cond());
   VALIDATE_PTHREAD_RESULT(result);
 }
 
 
 void Monitor::NotifyAll() {
   // TODO(iposva): Do we need to track lock owners?
   int result = pthread_cond_broadcast(data_.cond());
   VALIDATE_PTHREAD_RESULT(result);
 }
 
 }  // namespace dart