BuddyPress.org

This will work anyway if bp is switched off and when someone switch on it he will give a redeclaration error

Look here:

$active_plugins = get_site_option( 'active_sitewide_plugins' );

if ( isset( $active_plugins['buddypress/bp-loader.php'] ) )

require_once( BP_PLUGIN_DIR . 'bp-core.php' );

or making a system of hooks in hooks i made fo bpdev plugins to prevent “undefinied functions error”