patch 7.4.2243
Problem:    Warning for assigning negative value to unsigned. (Danek Duvall)
Solution:   Make cterm_normal_fg_gui_color and _bg_ guicolor_T, cast to long_u
            only when an unsigned is needed.
diff --git a/src/proto/gui_w32.pro b/src/proto/gui_w32.pro
index 20a92b9..2eccf74 100644
--- a/src/proto/gui_w32.pro
+++ b/src/proto/gui_w32.pro
@@ -35,7 +35,7 @@
 void gui_mch_set_menu_pos(int x, int y, int w, int h);
 void gui_mch_menu_hidden(vimmenu_T *menu, int hidden);
 void gui_mch_draw_menubar(void);
-long_u gui_mch_get_rgb(guicolor_T pixel);
+guicolor_T gui_mch_get_rgb(guicolor_T pixel);
 void gui_mch_activate_window(void);
 void gui_mch_show_toolbar(int showit);
 void gui_mch_show_tabline(int showit);