Homepage: https://github.com/emacs-compat/compat
Updated:
Emacs Lisp Compatibility Library
Compat is the Elisp forwards compatibility library, which provides definitions introduced in newer Emacs versions. The definitions are only installed if necessary for your current Emacs version. If Compat is compiled on a recent version of Emacs, all of the definitions are disabled at compile time, such that no negative performance impact is incurred. The provided compatibility implementations of functions and macros are at least subsets of the actual implementations. Be sure to read the documentation string and the Compat manual. Not every function provided in newer versions of Emacs is provided here. Some depend on new features from the C core, others cannot be implemented to a meaningful degree. Please consult the Compat manual for details regarding the usage of the Compat library and the provided functionality. The main audience for this library are not regular users, but package maintainers. Therefore no commands, user-facing modes or user options are implemented here.