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/gui_photon.c b/src/gui_photon.c
index 1000a5e..7b1462a 100644
--- a/src/gui_photon.c
+++ b/src/gui_photon.c
@@ -1933,10 +1933,11 @@
 /*
  * Return the RGB value of a pixel as a long.
  */
-    long_u
+    guicolor_T
 gui_mch_get_rgb(guicolor_T pixel)
 {
-    return PgRGB(PgRedValue(pixel), PgGreenValue(pixel), PgBlueValue(pixel));
+    return (guicolor_T)(PgRGB(PgRedValue(pixel),
+				     PgGreenValue(pixel), PgBlueValue(pixel)));
 }
 
     void