Use c++_static instead of stlport_static for support lib.

Bug: 27230989

  - Clean up the makefile
  - For NDK libs, use c++_static
  - Avoid exposing symbols for C++ lib
  - Use nullptr instead of NULL

Change-Id: I60cf11cb6a6044584a3e484979da231f72772f86
(cherry picked from commit 5abfd9b62b3173a371c42fc92ca8cf978420d694)
3 files changed