* doc/lispref/compile.texi (Native Compilation): Document
native-comp-available-p as the way to test for native compilation.
* lisp/emacs-lisp/package.el (package--native-compile-async):
* test/lisp/mh-e/mh-utils-tests.el (mh-ensure-native-trampolines):
Test for native compilation with native-comp-available-p.
Thank you to Andrea Corallo for reviewing this patch.