This way we set the two variables just before doing the
`native-comp-eln-load-path' job.  So essentially before the native
compiler is usable.

*Also* I'm now wondering if we shouldn't rename
 `comp-enable-subr-trampolines' into
 `native-comp-enable-subr-trampolines' (if it's not to late...)

> And I understand that you are suggesting that _in_addition_ to the
> patch I proposed, right?

I think my change should be sufficient, maybe you see a reason why we
should set these two every time we pass in `native-comp-available-p'?

Thanks

  Andrea