bp_set_theme_compat_feature( string $theme_id, array $feature = array() )

function bp_set_theme_compat_feature( $theme_id, $feature = array() ) {
	if ( empty( $theme_id ) || empty( $feature['name'] ) ) {
		return;
	}

	// Get BuddyPress instance.
	$bp = buddypress();

	// Get current theme compat theme.
	$theme_compat_theme = $bp->theme_compat->theme;

	// Bail if the Theme Compat theme is not in use.
	if ( $theme_id !== bp_get_theme_compat_id() ) {
		return;
	}

	$features = $theme_compat_theme->__get( 'features' );
	if ( empty( $features ) ) {
		$features = array();
	}

	// Bail if the feature is already registered or no settings were provided.
	if ( isset( $features[ $feature['name'] ] ) || empty( $feature['settings'] ) ) {
		return;
	}

	// Add the feature.
	$features[ $feature['name'] ] = (object) $feature['settings'];

	// The feature is attached to components.
	if ( isset( $features[ $feature['name'] ]->components ) ) {
		// Set the feature for each concerned component.
		foreach ( (array) $features[ $feature['name'] ]->components as $component ) {
			// The xProfile component is specific.
			if ( 'xprofile' === $component ) {
				$component = 'profile';
			}

			if ( isset( $bp->{$component} ) ) {
				if ( isset( $bp->{$component}->features ) ) {
					$bp->{$component}->features[] = $feature['name'];
				} else {
					$bp->{$component}->features = array( $feature['name'] );
				}
			}
		}
	}

	// Finally update the theme compat features.
	$theme_compat_theme->__set( 'features', $features );
}