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/screen.c b/src/screen.c
index 64e159a..b580aee 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -7865,7 +7865,7 @@
 	    else if (aep != NULL && cterm_normal_fg_bold &&
 #ifdef FEAT_TERMGUICOLORS
 			(p_tgc ?
-			    (aep->ae_u.cterm.fg_rgb != (long_u)INVALCOLOR):
+			    (aep->ae_u.cterm.fg_rgb != INVALCOLOR):
 #endif
 			    (t_colors > 1 && aep->ae_u.cterm.fg_color)
 #ifdef FEAT_TERMGUICOLORS
@@ -7894,9 +7894,9 @@
 #ifdef FEAT_TERMGUICOLORS
 		if (p_tgc)
 		{
-		    if (aep->ae_u.cterm.fg_rgb != (long_u)INVALCOLOR)
+		    if (aep->ae_u.cterm.fg_rgb != INVALCOLOR)
 			term_fg_rgb_color(aep->ae_u.cterm.fg_rgb);
-		    if (aep->ae_u.cterm.bg_rgb != (long_u)INVALCOLOR)
+		    if (aep->ae_u.cterm.bg_rgb != INVALCOLOR)
 			term_bg_rgb_color(aep->ae_u.cterm.bg_rgb);
 		}
 		else
@@ -7956,8 +7956,8 @@
 		    if (aep != NULL &&
 #ifdef FEAT_TERMGUICOLORS
 			    (p_tgc ?
-				(aep->ae_u.cterm.fg_rgb != (long_u)INVALCOLOR ||
-				 aep->ae_u.cterm.bg_rgb != (long_u)INVALCOLOR):
+				(aep->ae_u.cterm.fg_rgb != INVALCOLOR
+				 || aep->ae_u.cterm.bg_rgb != INVALCOLOR):
 #endif
 				(aep->ae_u.cterm.fg_color || aep->ae_u.cterm.bg_color)
 #ifdef FEAT_TERMGUICOLORS
@@ -8014,9 +8014,9 @@
 #ifdef FEAT_TERMGUICOLORS
 	    if (p_tgc)
 	    {
-		if (cterm_normal_fg_gui_color != (long_u)INVALCOLOR)
+		if (cterm_normal_fg_gui_color != INVALCOLOR)
 		    term_fg_rgb_color(cterm_normal_fg_gui_color);
-		if (cterm_normal_bg_gui_color != (long_u)INVALCOLOR)
+		if (cterm_normal_bg_gui_color != INVALCOLOR)
 		    term_bg_rgb_color(cterm_normal_bg_gui_color);
 	    }
 	    else
@@ -8049,10 +8049,9 @@
     {
 	/* set Normal cterm colors */
 #ifdef FEAT_TERMGUICOLORS
-	if (p_tgc ?
-		(cterm_normal_fg_gui_color != (long_u)INVALCOLOR
-		 || cterm_normal_bg_gui_color != (long_u)INVALCOLOR):
-		(cterm_normal_fg_color > 0 || cterm_normal_bg_color > 0))
+	if (p_tgc ? (cterm_normal_fg_gui_color != INVALCOLOR
+		 || cterm_normal_bg_gui_color != INVALCOLOR)
+		: (cterm_normal_fg_color > 0 || cterm_normal_bg_color > 0))
 #else
 	if (cterm_normal_fg_color > 0 || cterm_normal_bg_color > 0)
 #endif
@@ -8983,7 +8982,7 @@
 		|| gui.in_use
 #endif
 #ifdef FEAT_TERMGUICOLORS
-		|| (p_tgc && cterm_normal_bg_gui_color == (long_u)INVALCOLOR)
+		|| (p_tgc && cterm_normal_bg_gui_color == INVALCOLOR)
 		|| (!p_tgc && cterm_normal_bg_color == 0)
 #else
 		|| cterm_normal_bg_color == 0