Switch from POST_BY_EMAIL constant to enable post-by-email when multisite to a filter. See #12381.

git-svn-id: http://svn.automattic.com/wordpress/trunk@13416 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/options-writing.php

@@ -81,7 +81,7 @@ wp_dropdown_categories(array('hide_empty' => 0, 'name' => 'default_link_category
 <?php do_settings_fields('writing', 'remote_publishing'); ?>
 </table>
 
-<?php if ( !is_multisite() || defined( 'POST_BY_EMAIL' ) ) { ?>
+<?php if ( apply_filters( 'enable_post_by_email_configuration', true ) ) { ?>
 <h3><?php _e('Post via e-mail') ?></h3>
 <p><?php printf(__('To post to WordPress by e-mail you must set up a secret e-mail account with POP3 access. Any mail received at this address will be posted, so it&#8217;s a good idea to keep this address very secret. Here are three random strings you could use: <kbd>%s</kbd>, <kbd>%s</kbd>, <kbd>%s</kbd>.'), wp_generate_password(8, false), wp_generate_password(8, false), wp_generate_password(8, false)) ?></p>
 

wp-includes/ms-default-filters.php

@@ -39,4 +39,5 @@ add_action( 'phpmailer_init', 'fix_phpmailer_messageid' );
 
 // Disable somethings by default for multisite
 add_filter( 'enable_update_services_configuration', '__return_false' );
+add_filter( 'enable_post_by_email_configuration', '__return_false' );
 ?>