(x_defined_color, x_set_mouse_color, lookup_rgb_color)

(x_defined_color, x_set_mouse_color, lookup_rgb_color)
(lookup_pixel_color, x_laplace, x_build_heuristic_mask)
(png_load): Access colormap of frame using FRAME_X_COLORMAP.
(x_decode_color): Don't handle allocation of white and black
specially.
(x_window) [USE_X_TOOLKIT]: Set XtNvisual, XtNdepth, and
XtNcolormap resources.
(x_window) [!USE_X_TOOLKIT]: Pass colormap to XCreateWindow.
(Fx_create_frame): Initialize color members of x_output structure.
(xpm_load): Pass colormap to XPM lib.