NDK: x86 header file has incorrect definition for ptrdiff_t

See Bug http://code.google.com/p/android/issues/detail?id=19042

Change-Id: I8e975930e7f8c3c437ecdffbc6f6bc5028937829
Signed-off-by: Mark D Horn <mark.d.horn@intel.com>
diff --git a/libc/arch-x86/include/machine/_types.h b/libc/arch-x86/include/machine/_types.h
index 5e28c64..65892a1 100644
--- a/libc/arch-x86/include/machine/_types.h
+++ b/libc/arch-x86/include/machine/_types.h
@@ -51,7 +51,11 @@
 #endif
 #ifndef _PTRDIFF_T
 #define _PTRDIFF_T
-typedef long           ptrdiff_t;
+#  ifdef __ANDROID__
+     typedef int            ptrdiff_t;
+#  else
+     typedef long           ptrdiff_t;
+#  endif
 #endif
 
 #include <linux/types.h>