To reduce redundancy, remove the maintenance hassle that version
constants would impose later on, and rely on built-in
facilities (featurep) more over global variables or doomisms, these
global constants have been deprecated in favor of Emacs "features":
- EMACS28+ -- replace with (> emacs-major-version 27)
- EMACS29+ -- replace with (> emacs-major-version 28)
- NATIVECOMP -- replace with (featurep 'native-compile)
- MODULES -- replace with (featurep 'dynamic-modules)
(These constants will be formally removed when v3 is released. The IS-*
constants are likely next, but I haven't decided on their substitutes
yet)
I also decided to follow native-compile's example and provide features
for Emacs' system features (since system-configuration-features' docs
outs itself as a poor method to detect features):
- dynamic-modules
- jansson
- native-compile -- this one already exists, but will instead be removed
if it's non-functional; i.e. (native-comp-available-p) returns nil.
These are now detectable using featurep, which is fast and built-in.
Users (or packages) may add entries directly to prettify-symbols-alist.
The module would mistaken that as a green light to activate
prettify-symbols-mode. Instead, only activate the mode if this module's
ligatures (or extra symbols) are specifically asked for.
