Add tests that instantiate macros

[kainino0x]

With #158 we're going to have a nontrivial macro so we'll need to actually instantiate the macro to make sure it builds.

[kainino0x]

I started writing some, and here's a fun tidbit: ULL, and even UINT64_MAX, don't officially work before C++11.

./main.inl:20:22: error: 'long long' is a C++11 extension [-Werror,-Wc++11-long-long]
        uint64_t z = UINT64_MAX;
                     ^

[kainino0x]

We have some tests; all the remaining work is part of #158, so I'm just going to consolidate this into that.