GitLab

(x_set_mouse_color, x_set_cursor_color): Don't call unload_color
if same pixel is used in another slot in the frame.

(x_set_foreground_color): Call unload_color on the old color.
(x_set_background_color, x_set_mouse_color): Likewise.
(x_set_cursor_color, x_set_border_pixel): Likewise.