Don't rely on global _e and _x functions of laeh2

In commit
https://github.com/ypocat/laeh2/commit/d20c9f34f252c85a49b935970b413717cafb13c0
ypocat changed the behaviour of laeh2 so that _e and _x are no longer
added to the global space.
Hence we need the shorthands _e and _x to use laeh._e and laeh._x