diff --git a/include/private/android_filesystem_config.h b/include/private/android_filesystem_config.h
index a49da8c..b943e2c 100644
--- a/include/private/android_filesystem_config.h
+++ b/include/private/android_filesystem_config.h
@@ -26,7 +26,7 @@
 #include <sys/types.h>
 #include <stdint.h>
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 #include <linux/capability.h>
 #else
 #include "android_filesystem_capability.h"
diff --git a/include/utils/AndroidThreads.h b/include/utils/AndroidThreads.h
index aad1e82..4c2dd49 100644
--- a/include/utils/AndroidThreads.h
+++ b/include/utils/AndroidThreads.h
@@ -73,7 +73,7 @@
 // ------------------------------------------------------------------
 // Extra functions working with raw pids.
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 // Change the priority AND scheduling group of a particular thread.  The priority
 // should be one of the ANDROID_PRIORITY constants.  Returns INVALID_OPERATION
 // if the priority set failed, else another value if just the group set failed;
diff --git a/include/utils/Mutex.h b/include/utils/Mutex.h
index 757519b..f027c79 100644
--- a/include/utils/Mutex.h
+++ b/include/utils/Mutex.h
@@ -59,7 +59,7 @@
     // lock if possible; returns 0 on success, error otherwise
     status_t    tryLock();
 
-#if HAVE_ANDROID_OS
+#if defined(__ANDROID__)
     // lock the mutex, but don't wait longer than timeoutMilliseconds.
     // Returns 0 on success, TIMED_OUT for failure due to timeout expiration.
     //
@@ -128,7 +128,7 @@
 inline status_t Mutex::tryLock() {
     return -pthread_mutex_trylock(&mMutex);
 }
-#if HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 inline status_t Mutex::timedLock(nsecs_t timeoutNs) {
     const struct timespec ts = {
         /* .tv_sec = */ static_cast<time_t>(timeoutNs / 1000000000),
diff --git a/include/utils/Thread.h b/include/utils/Thread.h
index 28839fd..1532b7e 100644
--- a/include/utils/Thread.h
+++ b/include/utils/Thread.h
@@ -70,7 +70,7 @@
     // Indicates whether this thread is running or not.
             bool        isRunning() const;
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
     // Return the thread's kernel ID, same as the thread itself calling gettid(),
     // or -1 if the thread is not running.
             pid_t       getTid() const;
@@ -101,7 +101,7 @@
     volatile bool           mExitPending;
     volatile bool           mRunning;
             sp<Thread>      mHoldSelf;
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
     // legacy for debugging, not used by getTid() as it is set by the child thread
     // and so is not initialized until the child reaches that point
             pid_t           mTid;
diff --git a/include/utils/Trace.h b/include/utils/Trace.h
index 6ee343d..6ba68f6 100644
--- a/include/utils/Trace.h
+++ b/include/utils/Trace.h
@@ -17,7 +17,7 @@
 #ifndef ANDROID_TRACE_H
 #define ANDROID_TRACE_H
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 
 #include <fcntl.h>
 #include <stdint.h>
@@ -59,11 +59,11 @@
 
 }; // namespace android
 
-#else // HAVE_ANDROID_OS
+#else // !__ANDROID__
 
 #define ATRACE_NAME(...)
 #define ATRACE_CALL()
 
-#endif // HAVE_ANDROID_OS
+#endif // __ANDROID__
 
 #endif // ANDROID_TRACE_H
diff --git a/libcutils/iosched_policy.c b/libcutils/iosched_policy.c
index 8946d3c..71bc94b 100644
--- a/libcutils/iosched_policy.c
+++ b/libcutils/iosched_policy.c
@@ -23,7 +23,7 @@
 
 #include <cutils/iosched_policy.h>
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 #include <linux/ioprio.h>
 #include <sys/syscall.h>
 #define __android_unused
@@ -32,7 +32,7 @@
 #endif
 
 int android_set_ioprio(int pid __android_unused, IoSchedClass clazz __android_unused, int ioprio __android_unused) {
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
     if (syscall(SYS_ioprio_set, IOPRIO_WHO_PROCESS, pid, ioprio | (clazz << IOPRIO_CLASS_SHIFT))) {
         return -1;
     }
@@ -41,7 +41,7 @@
 }
 
 int android_get_ioprio(int pid __android_unused, IoSchedClass *clazz, int *ioprio) {
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
     int rc;
 
     if ((rc = syscall(SYS_ioprio_get, IOPRIO_WHO_PROCESS, pid)) < 0) {
diff --git a/libcutils/process_name.c b/libcutils/process_name.c
index cc931eb..5d28b6f 100644
--- a/libcutils/process_name.c
+++ b/libcutils/process_name.c
@@ -25,19 +25,19 @@
 #include <unistd.h>
 
 #include <cutils/process_name.h>
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 #include <cutils/properties.h>
 #endif
 
 #define PROCESS_NAME_DEVICE "/sys/qemu_trace/process_name"
 
 static const char* process_name = "unknown";
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 static int running_in_emulator = -1;
 #endif
 
 void set_process_name(const char* new_name) {
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
     char  propBuf[PROPERTY_VALUE_MAX];
 #endif
 
@@ -59,7 +59,7 @@
     }
 #endif
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
     // If we know we are not running in the emulator, then return.
     if (running_in_emulator == 0) {
         return;
diff --git a/libcutils/sched_policy.c b/libcutils/sched_policy.c
index ab0331d..298e3da 100644
--- a/libcutils/sched_policy.c
+++ b/libcutils/sched_policy.c
@@ -37,7 +37,7 @@
    return p == SP_DEFAULT ? SP_SYSTEM_DEFAULT : p;
 }
 
-#if defined(HAVE_ANDROID_OS)
+#if defined(__ANDROID__)
 
 #include <pthread.h>
 #include <sched.h>
@@ -146,7 +146,7 @@
  */
 static int getSchedulerGroup(int tid, char* buf, size_t bufLen)
 {
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
     char pathBuf[32];
     char lineBuf[256];
     FILE *fp;
diff --git a/libcutils/sockets.c b/libcutils/sockets.c
index 15ede2b..d438782 100644
--- a/libcutils/sockets.c
+++ b/libcutils/sockets.c
@@ -17,7 +17,7 @@
 #include <cutils/sockets.h>
 #include <log/log.h>
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 /* For the socket trust (credentials) check */
 #include <private/android_filesystem_config.h>
 #define __android_unused
@@ -27,7 +27,7 @@
 
 bool socket_peer_is_trusted(int fd __android_unused)
 {
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
     struct ucred cr;
     socklen_t len = sizeof(cr);
     int n = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cr, &len);
diff --git a/libnativebridge/native_bridge.cc b/libnativebridge/native_bridge.cc
index a9671a9..32a65ea 100644
--- a/libnativebridge/native_bridge.cc
+++ b/libnativebridge/native_bridge.cc
@@ -295,13 +295,13 @@
   // so we save the extra file existence check.
   char cpuinfo_path[1024];
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
   snprintf(cpuinfo_path, sizeof(cpuinfo_path), "/system/lib"
 #ifdef __LP64__
       "64"
 #endif  // __LP64__
       "/%s/cpuinfo", instruction_set);
-#else   // !HAVE_ANDROID_OS
+#else   // !__ANDROID__
   // To be able to test on the host, we hardwire a relative path.
   snprintf(cpuinfo_path, sizeof(cpuinfo_path), "./cpuinfo");
 #endif
diff --git a/libnativebridge/tests/PreInitializeNativeBridge_test.cpp b/libnativebridge/tests/PreInitializeNativeBridge_test.cpp
index cec26ce..d3bbebe 100644
--- a/libnativebridge/tests/PreInitializeNativeBridge_test.cpp
+++ b/libnativebridge/tests/PreInitializeNativeBridge_test.cpp
@@ -32,8 +32,8 @@
 
 TEST_F(NativeBridgeTest, PreInitializeNativeBridge) {
     ASSERT_TRUE(LoadNativeBridge(kNativeBridgeLibrary, nullptr));
-#ifndef __APPLE__         // Mac OS does not support bind-mount.
-#ifndef HAVE_ANDROID_OS   // Cannot write into the hard-wired location.
+#if !defined(__APPLE__)         // Mac OS does not support bind-mount.
+#if !defined(__ANDROID__)       // Cannot write into the hard-wired location.
     // Try to create our mount namespace.
     if (unshare(CLONE_NEWNS) != -1) {
         // Create a dummy file.
diff --git a/libnetutils/ifc_utils.c b/libnetutils/ifc_utils.c
index 7d2a5fb..956ed30 100644
--- a/libnetutils/ifc_utils.c
+++ b/libnetutils/ifc_utils.c
@@ -50,7 +50,7 @@
 #define ALOGW printf
 #endif
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 /* SIOCKILLADDR is an Android extension. */
 #define SIOCKILLADDR 0x8939
 #endif
@@ -596,7 +596,7 @@
 
 int ifc_reset_connections(const char *ifname, const int reset_mask)
 {
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
     int result, success;
     in_addr_t myaddr = 0;
     struct ifreq ifr;
diff --git a/libutils/SystemClock.cpp b/libutils/SystemClock.cpp
index 64204a8..1fca2b2 100644
--- a/libutils/SystemClock.cpp
+++ b/libutils/SystemClock.cpp
@@ -19,7 +19,7 @@
  * System clock functions.
  */
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 #include <linux/ioctl.h>
 #include <linux/rtc.h>
 #include <utils/Atomic.h>
@@ -107,7 +107,7 @@
  */
 int64_t elapsedRealtimeNano()
 {
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
     struct timespec ts;
     int result;
     int64_t timestamp;
diff --git a/libutils/Threads.cpp b/libutils/Threads.cpp
index c3666e4..6dda6b5 100644
--- a/libutils/Threads.cpp
+++ b/libutils/Threads.cpp
@@ -45,7 +45,7 @@
 
 #include <cutils/sched_policy.h>
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 # define __android_unused
 #else
 # define __android_unused __attribute__((__unused__))
@@ -132,7 +132,7 @@
     pthread_attr_init(&attr);
     pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 
-#ifdef HAVE_ANDROID_OS  /* valgrind is rejecting RT-priority create reqs */
+#if defined(__ANDROID__)  /* valgrind is rejecting RT-priority create reqs */
     if (threadPriority != PRIORITY_DEFAULT || threadName != NULL) {
         // Now that the pthread_t has a method to find the associated
         // android_thread_id_t (pid) from pthread_t, it would be possible to avoid
@@ -176,7 +176,7 @@
     return 1;
 }
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 static pthread_t android_thread_id_t_to_pthread(android_thread_id_t thread)
 {
     return (pthread_t) thread;
@@ -302,12 +302,10 @@
     gCreateThreadFn = func;
 }
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 int androidSetThreadPriority(pid_t tid, int pri)
 {
     int rc = 0;
-
-#if !defined(_WIN32)
     int lasterr = 0;
 
     if (pri >= ANDROID_PRIORITY_BACKGROUND) {
@@ -325,17 +323,12 @@
     } else {
         errno = lasterr;
     }
-#endif
 
     return rc;
 }
 
 int androidGetThreadPriority(pid_t tid) {
-#if !defined(_WIN32)
     return getpriority(PRIO_PROCESS, tid);
-#else
-    return ANDROID_PRIORITY_NORMAL;
-#endif
 }
 
 #endif
@@ -658,7 +651,7 @@
         mLock("Thread::mLock"),
         mStatus(NO_ERROR),
         mExitPending(false), mRunning(false)
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
         , mTid(-1)
 #endif
 {
@@ -728,7 +721,7 @@
     wp<Thread> weak(strong);
     self->mHoldSelf.clear();
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
     // this is very useful for debugging with gdb
     self->mTid = gettid();
 #endif
@@ -839,7 +832,7 @@
     return mRunning;
 }
 
-#ifdef HAVE_ANDROID_OS
+#if defined(__ANDROID__)
 pid_t Thread::getTid() const
 {
     // mTid is not defined until the child initializes it, and the caller may need it earlier
diff --git a/libutils/Timers.cpp b/libutils/Timers.cpp
index fb70e15..201bc41 100644
--- a/libutils/Timers.cpp
+++ b/libutils/Timers.cpp
@@ -23,7 +23,7 @@
 #include <sys/time.h>
 #include <time.h>
 
-#if defined(HAVE_ANDROID_OS)
+#if defined(__ANDROID__)
 nsecs_t systemTime(int clock)
 {
     static const clockid_t clocks[] = {