Re: [PATCH] blame: add blame.showemail config option

> Right. Rather than having a separate global 'show_email' variable and
> consulting that variable in parallel with OUTPUT_SHOW_EMAIL throughout
> the code, instead set the OUTPUT_SHOW_EMAIL bit in git_blame_config().
> To do this, take advantage of the "callback data" argument of
> git_config(), which will arrive in git_blame_config() as its 'void
> *cb' argument. So, for instance, something like this:
>
>     static int git_blame_config(var, value, void *cb)
>     {
>         ...
>         if (!strcmp(var, "blame.showemail")) {
>             if (git_config_bool(var, value)) {
>                 int *output_options = cb;
>                *output_options |= OUTPUT_SHOW_EMAIL;
>             }

>             return 0;
>         }
>         ...
>     }
>
>     int cmd_blame(...)
>     {
>         ...
>         git_config(git_blame_config, &output_options);
>         ...
>         parse_options(...);
>         ...
>     }