[notmuch] [PATCH] [RFC] notmuch search: Return a non-zero exitcode if the search returns no hits.

If the user is explicitly searching for a message, then if notmuch fails to find it, it is useful to set a failure exit code. This makes it easier for scripting. However, we will want to then distinguish between fatal errors (such as out-of-memory, invalid arguments, corrupt db, etc) from the

[notmuch] [PATCH] [RFC] notmuch search: Return a non-zero exitcode if the search returns no hits.

If the user is explicitly searching for a message, then if notmuch fails to find it, it is useful to set a failure exit code. This makes it easier for scripting. However, we will want to then distinguish between fatal errors (such as out-of-memory, invalid arguments, corrupt db, etc) from the