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This updates the Android makefile so it is able to build again.
Notable changes:
 - add x509x source files to DTLS code
 - changed default value for ANDROID_API from 19 to 23
 - added default values for DYNAMIC, SECURE, and PKI build options
 - updated starting CFLAGS value
   - -fPIE -pie changed to -fPIC
   - -fno-reorder-functions and -fno-defer-pop were removed
     due to warnings about them being unknown tags
 - add misc. security files to the build.

The tcpadapter code is a straight copy/paste of the tcpadapter.c/.h
from the Linux port. No modifications were made to tcpadapter.
Only changes made were:
 - added the adapter_receive_state_t to ipcontext.h needed by
   tcpadapter.

Most Makefile changes were obtained by referencing the Makefile
found in the `swig` branch.

Change-Id: Ifddcac31ad60a42c363206e397760a57466a551a
Signed-off-by: George Nash <george.nash@intel.com>