NDK: Last cleanup of the platform headers

- fix a declaration omission in 3/<grp.h>
- add missing 8/<err.h>
- simplify 8/<stdio.h>
- update 9/ headers to the latest Bionic versions
- fix a typo in android_native_app_glue.h
- use __BEGIN_DECLS .. __END_DECLS whenever possible.
- remove C++-style comments from headers

Change-Id: I58b98b3973cde494436206194ba33416a11ca8ee

ndk/platforms/android-9/include/android/bitmap.h

@@ -17,12 +17,11 @@
 #ifndef ANDROID_BITMAP_H
 #define ANDROID_BITMAP_H
 
+#include <sys/cdefs.h>
 #include <stdint.h>
 #include <jni.h>
 
-#ifdef __cplusplus
-extern "C" {
-#endif
+__BEGIN_DECLS
 
 #define ANDROID_BITMAP_RESUT_SUCCESS            0
 #define ANDROID_BITMAP_RESULT_BAD_PARAMETER     -1
@@ -72,8 +71,6 @@ int AndroidBitmap_lockPixels(JNIEnv* env, jobject jbitmap, void** addrPtr);
  */
 int AndroidBitmap_unlockPixels(JNIEnv* env, jobject jbitmap);
 
-#ifdef __cplusplus
-}
-#endif
+__END_DECLS
 
-#endif
+#endif /* ANDROID_BITMAP_H */