include: make header guards more sane The C++ standard[1] says: Each identifier that contains a double underscore __ or begins with an underscore followed by an uppercase letter is reserved to the implementation for any use. [1]: https://timsong-cpp.github.io/cppwp/n4659/lex.name#3.1

<transition source="idle" target="run">
	<event name="key_up|key_shift" />
</transition>
<transition source="run" target="attack">
	<event name="key_ctrl" />
	<condition expr="weapon != null" />
</transition>