Unify NDK platform headers.
This commit removes duplication of system headers per platform, i.e. remove
copies of common headers like <stdlib.h> from arch-arm/usr/include and arch-x86/usr/include
and move them to a common include directory. More specifically:
- common headers: android-N/arch-A/usr/include --> android-N/include
- arch-specific headers: android-N/arch-A/usr-include --> android-N/arch-A/include
- arch-specific libs: android-N/arch-A/usr/lib --> android-N/arch-A/lib
Change-Id: Ifdba5038d108901931f3e3a7c14ebe6270d2d276
NOTE: This also contains careful separation of API-level-specific headers.
For example, platforms/android-5/include/pthread.h contains new function
declarations that are not available when using platforms/android-3/include/pthread.h
NOTE: The NDK's build-platforms.sh script has been updated to understand the new
layout. This change in develeopment/ndk does not change the layout of
platform files under $NDK/platforms after build-platforms.sh is called.