/*
 * Get the default X11 Colormap on the specified Display and screen.
 * Raises a RunTimeError exception if the colormap could not be
 * allocated.
 *
 * Note: This method is not available unless Imlib2-Ruby was compiled
 * with X11 support.  You can check the constant Imlib2::X11_SUPPORT to
 * see if X11 support is available.
 *
 * Examples:
 *   cmap = Imlib2::X11::Colormap.new display, screen_num
 *
 */
VALUE cmap_new(VALUE klass, VALUE display, VALUE screen) {