Ports: Ability to enable or disable all SGB features (closes #1205)

CHANGES

@@ -13,6 +13,7 @@ Features:
  - Interframe blending for games that use flicker effects
  - Frame inspector for dissecting and debugging rendering
  - Switch: Option to use built-in brightness sensor for Boktai
+ - Ports: Ability to enable or disable all SGB features (closes mgba.io/i/1205)
 Emulation fixes:
  - GBA: All IRQs have 7 cycle delay (fixes mgba.io/i/539, mgba.io/i/1208)
  - GBA: Reset now reloads multiboot ROMs

src/feature/gui/gui-config.c

@@ -118,6 +118,20 @@ void mGUIShowConfig(struct mGUIRunner* runner, struct GUIMenuItem* extra, size_t
 		},
 		.nStates = 2
 	};
+	*GUIMenuItemListAppend(&menu.items) = (struct GUIMenuItem) {
+		.title = "Enable SGB features",
+		.data = "sgb.model",
+		.submenu = 0,
+		.state = true,
+		.validStates = (const char*[]) {
+			"Off", "On"
+		},
+		.stateMappings = (const struct GUIVariant[]) {
+			GUI_V_S("DMG"),
+			GUI_V_S("SGB"),
+		},
+		.nStates = 2
+	};
 	*GUIMenuItemListAppend(&menu.items) = (struct GUIMenuItem) {
 		.title = "Enable SGB borders",
 		.data = "sgb.borders",
@@ -173,8 +187,6 @@ void mGUIShowConfig(struct mGUIRunner* runner, struct GUIMenuItem* extra, size_t
 			continue;
 		}
 		if (item->stateMappings) {
-			item->state = 0;
-
 			size_t j;
 			for (j = 0; j < item->nStates; ++j) {
 				const struct GUIVariant* v = &item->stateMappings[j];