aac project forces the system not to include sys/types.h by defining
_SYS_TYPES_H_. This is a workaround for broken android toolchain.

This is no longer needed in latest android version and can be safely
removed. This will also lead to more errors if changes in bionic
headers are needed.

Change-Id: Icb76c207d6b47e811eacff9f9403177629bfb451
Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>