native-comp: load-true-file-name compatibility

[Kevin Liu]

I have come across some code that looks like this:

(defconst sayid-version
  (eval-when-compile (lm-version load-file-name)))

In native-comp I believe it has to use load-true-file-name instead,
however this variable only exists in native-comp.  What is a good way
to make this code compatible for both branches?