Re: [PATCH v2 3/5] hook API: support passing stdin to hooks, convert am's 'post-rewrite'

> From: Emily Shaffer <emilyshaffer@google.com>
>
> Convert the invocation of the 'post-rewrite' hook run by 'git am' to
> use the hook.h library. To do this we need to add a "path_to_stdin"
> member to "struct run_hooks_opt".
>
> In our API this is supported by asking for a file path, rather
> than by reading stdin. Reading directly from stdin would involve caching
> the entire stdin (to memory or to disk) once the hook API is made to
> support "jobs" larger than 1, along with support for executing N hooks
> at a time (i.e. the upcoming config-based hooks).