bug#23219: 25.0.92; Find command cannot be customized for grep-find

[Dmitry Gutov <dgutov@yandex.ru>]

On 04/05/2016 06:01 PM, Eli Zaretskii wrote:

> -(defvar grep-program (purecopy "grep")
> +(defcustom grep-grep-program (purecopy "grep")

I didn't mean to suggest renaming the variables. At the very least, we'd 
need obsolete aliases, as they're likely to be used in some third party 
code.

Also, grep-grep-program looks weird.

>    "The default grep program for `grep-command' and `grep-find-command'.
> -This variable's value takes effect when `grep-compute-defaults' is called.")
> +This variable's value takes effect when `grep-compute-defaults' is called."
> +  :type 'string
> +  :set 'grep-apply-setting

Does grep-apply-setting expect the new variables? Its docstring disagrees.