Add and use constants for the Android API levels.

Test: bionic tests still pass
Change-Id: If1b619cfc9db1d3f5d91f14f2ace71058dca0c4a
diff --git a/tests/semaphore_test.cpp b/tests/semaphore_test.cpp
index 7dc7225..24a2dbe 100644
--- a/tests/semaphore_test.cpp
+++ b/tests/semaphore_test.cpp
@@ -188,7 +188,7 @@
 
 TEST(semaphore, sem_wait_no_EINTR_in_sdk_less_equal_than_23) {
 #if defined(__BIONIC__)
-  android_set_application_target_sdk_version(23U);
+  android_set_application_target_sdk_version(__ANDROID_API_M__);
   sem_t s;
   ASSERT_EQ(0, sem_init(&s, 0, 0));
   ScopedSignalHandler handler(SIGUSR1, sem_wait_test_signal_handler);