Build Integration, Standard Library, and Arithmetic Tests

Added CMake build to support unit testing in Unity framework
Implemented integer comparison tests from gcc libstdc++-v3
Added modular arithmetic unit tests for cmp_equal

Safe Integer Comparisons

General availability release of safe integer comparisons.

Safe Integer Comparisons

Initial release of safe integer comparison functions using type generic macros and GNU expression statements. This is a C port of the C++20 utility functions described here: https://en.cppreference.com/w/cpp/utility/intcmp