Make android_get_application_target_sdk_version available to the NDK.

Also move this and android_get_device_api_level into <android/api-level.h>
so that they're always available.

This involves cleaning up <sys/cdefs.h> slightly.

Bug: N/A
Test: builds
Change-Id: I25435c55f3549cd0d827a7581bee75ea8228028b
diff --git a/libc/bionic/pthread_mutex.cpp b/libc/bionic/pthread_mutex.cpp
index fda0b93..d9ddf10 100644
--- a/libc/bionic/pthread_mutex.cpp
+++ b/libc/bionic/pthread_mutex.cpp
@@ -42,7 +42,6 @@
 #include "private/bionic_constants.h"
 #include "private/bionic_fortify.h"
 #include "private/bionic_futex.h"
-#include "private/bionic_sdk_version.h"
 #include "private/bionic_systrace.h"
 #include "private/bionic_time_conversions.h"
 #include "private/bionic_tls.h"
@@ -789,7 +788,7 @@
 // ARM64. So make it noinline.
 static int __attribute__((noinline)) HandleUsingDestroyedMutex(pthread_mutex_t* mutex,
                                                                const char* function_name) {
-    if (bionic_get_application_target_sdk_version() >= __ANDROID_API_P__) {
+    if (android_get_application_target_sdk_version() >= __ANDROID_API_P__) {
         __fortify_fatal("%s called on a destroyed mutex (%p)", function_name, mutex);
     }
     return EBUSY;