* Map NULL to nullptr or __null when c++ compiler is used.
* Map STATIC_ASSERT to static_assert when a c++ compiler is used.
* Typecast RETURN_SUCCESS to type RETURN_STATUS to match type used
by all return error/warning status codes. C++ has stricter type
checking and found this inconsistency.
Cc: Liming Gao <gaoliming@byosoft.com.cn> Cc: Zhiguang Liu <zhiguang.liu@intel.com> Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com> Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>