Re: Finalizing 'inhibit-automatic-native-compilation'

[Andrea Corallo <akrl@sdf.org>]

Hello all,

at feature/inhibit-native-comp-cleanup I've pushed the branch I'm
testing that:

  . removes the EMACS_INHIBIT_AUTOMATIC_NATIVE_COMPILATION environment
    variable
  . removes `inhibit-automatic-native-compilation' variable and uses
    `native-comp-deferred-compilation', with or without
    `comp-enable-subr-trampolines' (as needed), instead
  . adds a third possible value to `comp-enable-subr-trampolines', a
    string that specifies a directory in which to deposit the JIT
    compiled trampolines
  . updates the doc string of `native-comp-never-optimize-functions' to
    mention its effect on trampolines
  . updates some do doc here and there accordingly 


Few notes:

- I think renaming `native-comp-deferred-compilation' to
  `native-comp-jit-compilation' might be more descriptive to the user
  but I guess we are late now? :/

- If `comp-enable-subr-trampolines' is meant to be used by the user we
  should probably rename it into `native-comp-enable-subr-trampolines'?
  I guess we are late as well?

- I left the piece of code that, when removing an eln file on windows,
  guards for errors.  This to be extra cautious, I'm not aware of any
  exection path were we should remove an eln while loaded now, but maybe
  we could remove that piece of code only on the emacs-30 branch.

Please have a look, seems to work here.

Last question for my knowledge: what's the exact reason why we want a
third possible value for `comp-enable-subr-trampolines' and we can use
`native-comp-eln-load-path' to redirect the trampoline compilation?  Is
this to support packagers wanting to produce eln files only for packages
but not for trampolines?

Bests Regards

  Andrea