* lisp/subr.el (alist-get): New accessor.

* lisp/subr.el (alist-get): New accessor.
* lisp/emacs-lisp/gv.el (alist-get): Provide expander.
* lisp/winner.el (winner-remember):
* lisp/tempo.el (tempo-use-tag-list):
* lisp/progmodes/gud.el (minor-mode-map-alist):
* lisp/international/mule-cmds.el (define-char-code-property):
* lisp/frameset.el (frameset-filter-params):
* lisp/files.el (dir-locals-set-class-variables):
* lisp/register.el (get-register, set-register):
* lisp/calc/calc-yank.el (calc-set-register): Use it.
* lisp/ps-print.el (ps-get, ps-put, ps-del): Mark as obsolete.
* lisp/tooltip.el (tooltip-set-param): Mark as obsolete.
(tooltip-show): Use alist-get instead.
* lisp/ses.el (ses--alist-get): Remove.  Use alist-get instead.
* admin/unidata/unidata-gen.el (unidata-gen-table-word-list): Use alist-get
and cl-incf.