How to configure packages, which have no
(provide <PACKAGENAME>) call in their source code?
Immediate problem: configure
isearch with use-package.
isearch.el is not an option because it may break updates and may trigger heavy bug hunting)
Edit: answering Drews comment:
use-package can be used to cluster elisp code, which should belong to a package/library. The user is then able to write functions or set up keybindings, which are part of a users emacs configuration. Whith this technique it is possible to lazy load self written functions, or even redefine functions from a package after the package/library has been loaded. (Of course there are also other ways to do that but use-package is a nice Domain Specific Language for that kind of configuration).
By "configure" I mean writing a valid
use-package sexp which serves the purpose of changing emacs default behavior.
Yes, with "Editing" I meant changing the source code file isearch.el. Emacs is hackable after all.