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.

ndk/platforms/android-3/include/linux/lockd/nlm.h

@@ -0,0 +1,50 @@
+/****************************************************************************
+ ****************************************************************************
+ ***
+ ***   This header was automatically generated from a Linux kernel header
+ ***   of the same name, to make information necessary for userspace to
+ ***   call into the kernel available to libc.  It contains only constants,
+ ***   structures, and macros generated from the original header, and thus,
+ ***   contains no copyrightable information.
+ ***
+ ****************************************************************************
+ ****************************************************************************/
+#ifndef LINUX_LOCKD_NLM_H
+#define LINUX_LOCKD_NLM_H
+
+#define NLM_OFFSET_MAX ((s32) 0x7fffffff)
+#define NLM4_OFFSET_MAX ((s64) ((~(u64)0) >> 1))
+
+enum {
+ NLM_LCK_GRANTED = 0,
+ NLM_LCK_DENIED = 1,
+ NLM_LCK_DENIED_NOLOCKS = 2,
+ NLM_LCK_BLOCKED = 3,
+ NLM_LCK_DENIED_GRACE_PERIOD = 4,
+};
+
+#define NLM_PROGRAM 100021
+
+#define NLMPROC_NULL 0
+#define NLMPROC_TEST 1
+#define NLMPROC_LOCK 2
+#define NLMPROC_CANCEL 3
+#define NLMPROC_UNLOCK 4
+#define NLMPROC_GRANTED 5
+#define NLMPROC_TEST_MSG 6
+#define NLMPROC_LOCK_MSG 7
+#define NLMPROC_CANCEL_MSG 8
+#define NLMPROC_UNLOCK_MSG 9
+#define NLMPROC_GRANTED_MSG 10
+#define NLMPROC_TEST_RES 11
+#define NLMPROC_LOCK_RES 12
+#define NLMPROC_CANCEL_RES 13
+#define NLMPROC_UNLOCK_RES 14
+#define NLMPROC_GRANTED_RES 15
+#define NLMPROC_NSM_NOTIFY 16  
+#define NLMPROC_SHARE 20
+#define NLMPROC_UNSHARE 21
+#define NLMPROC_NM_LOCK 22
+#define NLMPROC_FREE_ALL 23
+
+#endif