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/include/bits/get_device_api_level_inlines.h b/libc/include/bits/get_device_api_level_inlines.h
index 8e17814..9c6e243 100644
--- a/libc/include/bits/get_device_api_level_inlines.h
+++ b/libc/include/bits/get_device_api_level_inlines.h
@@ -28,18 +28,20 @@
 
 #pragma once
 
-#include <stdlib.h>
 #include <sys/cdefs.h>
-#include <sys/system_properties.h>
 
 #if !defined(__BIONIC_GET_DEVICE_API_LEVEL_INLINE)
-#define __BIONIC_GET_DEVICE_API_LEVEL_INLINE static __inline
+#define __BIONIC_GET_DEVICE_API_LEVEL_INLINE static inline /* for versioner */
 #endif
 
 __BEGIN_DECLS
 
+// Avoid circular dependencies since this is exposed from <sys/cdefs.h>.
+int __system_property_get(const char* __name, char* __value);
+int atoi(const char* __s) __attribute_pure__;
+
 __BIONIC_GET_DEVICE_API_LEVEL_INLINE int android_get_device_api_level() {
-  char value[PROP_VALUE_MAX] = { 0 };
+  char value[92] = { 0 };
   if (__system_property_get("ro.build.version.sdk", value) < 1) return -1;
   int api_level = atoi(value);
   return (api_level > 0) ? api_level : -1;
diff --git a/libc/include/bits/ioctl.h b/libc/include/bits/ioctl.h
index 9ed1292..fd31a58 100644
--- a/libc/include/bits/ioctl.h
+++ b/libc/include/bits/ioctl.h
@@ -54,11 +54,8 @@
  *   type of the ioctl you prefer, ...), or
  * - defining BIONIC_IOCTL_NO_SIGNEDNESS_OVERLOAD, which will make the
  *   overloading go away.
- *
- * FIXME: __has_extension is more or less a clang version check. Remove it when
- * we don't need to support old clang code.
  */
-#if __has_extension(overloadable_unmarked) && !defined(BIONIC_IOCTL_NO_SIGNEDNESS_OVERLOAD)
+#if !defined(BIONIC_IOCTL_NO_SIGNEDNESS_OVERLOAD)
 /* enable_if(1) just exists to break overloading ties. */
 int ioctl(int __fd, unsigned __request, ...) __overloadable __enable_if(1, "") __RENAME(ioctl);
 #endif