commit https://github.com/vim/vim/commit/1b58cdd160c2e0ada0f638679a2aa27e4665fc48 Author: Bram Moolenaar <Bram@vim.org> Date: Mon Aug 22 23:04:33 2016 +0200 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.

--- a/src/gui_mac.c
+++ b/src/gui_mac.c
@@ -5181,10 +5181,10 @@ gui_mch_start_blink(void)
 /*
  * Return the RGB value of a pixel as long.
  */
-    long_u
+    guicolor_T
 gui_mch_get_rgb(guicolor_T pixel)
 {
-    return (Red(pixel) << 16) + (Green(pixel) << 8) + Blue(pixel);
+    return (guicolor_T)((Red(pixel) << 16) + (Green(pixel) << 8) + Blue(pixel));
 }