function onGlob( error, files ) {
		if ( error ) {
			debug( 'Encountered an error when searching for files: %s', error.message );
			return cb( error );
		}
		if ( !files.length ) {
			debug( 'No files found.' );
			return cb( null, false );
		}
		if ( out === void 0 ) {
			return bundle( files, onBundle );
		}
		bundle( files, out, onBundle );
	}
Callback invoked upon matching files.

@private
@param {(Error|null)} error - error object
@param {StringArray} files - matches
@returns {void}