Add 'inhibit-native-compilation'

Add 'inhibit-native-compilation'

The following upstream patch has been backported:

  Add new variable 'inhibit-native-compilation'

  * lisp/startup.el (normal-top-level): Set
  inhibit-native-compilation from environment variable.

  * lisp/emacs-lisp/comp.el (comp-trampoline-compile): Don't write
  trampolines to disk.

  * lisp/progmodes/elisp-mode.el
  (emacs-lisp-native-compile-and-load): Adjust.

  * src/comp.c (syms_of_comp): New variable
  inhibit-native-compilation.
  (maybe_defer_native_compilation): Use it.

Origin: upstream, commit: 5fec9182dbeffa88cef6651d8c798ef9665d6681
Forwarded: not-needed