CI testing

fix MSVC errors and warnings

- strcasecmp is __stricmp in windows
- toml::array::for_each with if constexpr causes MSVC to fail evaluating noexcept specifiers for visit(), use for auto instead.
- engine functions defined in cpp are declared outside extern C blocks
- size_t to int narrowing is explicit where intentional.
- use %zu size_t printf specifier