LOCAL_MAILER_EOL

Overrides the default end-of-line string for the local mailer. 

LOCAL_MAILER_FLAGS

Adds Return-Path: header by default.

MAIL_SETTINGS_DIR

Contains the path (including the trailing slash) for the mail settings directory. 

MODIFY_MAILER_FLAGS

Improves the *_MAILER_FLAGS. This macro sets, adds, or deletes flags.

RELAY_MAILER_FLAGS

Defines additional flags for the relay mailer. 

USENET_MAILER_FLAGS

Is not a local mailer. Therefore, the l flag has been removed.