branch scratch/derived-mode-add-parents created (now 0939433b63a)

[Stefan Monnier]

monnier pushed a change to branch scratch/derived-mode-add-parents.

        at  0939433b63a Move EIEIO's C3 linearization code to `subr.el`

This branch includes the following new commits:

       new  19445b6b7bb subr.el: Provide a functional API around 
`derived-mode-parent`
       new  9c6b22bb3e2 (derived-mode-all-parents): Speed up with a cache
       new  492920dd5b4 Use new `derived-mode-all/set-parents` functions.
       new  5afa55a946a subr.el: Add multiple inheritance to `derived-mode-p`
       new  8323394bc80 Use `derived-mode-add-parents` in remaining uses of 
`derived-mode-parent`
       new  0939433b63a Move EIEIO's C3 linearization code to `subr.el`