Set XMB icon theme by default to Monochrome, and fix hardcoding

config.def.h

@@ -518,6 +518,8 @@ static bool default_block_config_read = true;
 
 static unsigned xmb_scale_factor = 100;
 static unsigned xmb_alpha_factor = 75;
+
+static unsigned xmb_icon_theme   = XMB_ICON_THEME_MONOCHROME;
 static unsigned xmb_theme        = XMB_THEME_ELECTRIC_BLUE;
 
 #ifdef HAVE_LAKKA

menu/cbs/menu_cbs_get_value.c

@@ -678,19 +678,19 @@ static void menu_action_setting_disp_set_label_xmb_theme(
    *w = 19;
    switch (settings->menu.xmb.theme)
    {
-      case 0:
+      case XMB_ICON_THEME_MONOCHROME:
          strlcpy(s, "Monochrome", len);
          break;
-      case 1:
+      case XMB_ICON_THEME_FLATUI:
          strlcpy(s, "FlatUI", len);
          break;
-      case 2:
+      case XMB_ICON_THEME_RETROACTIVE:
          strlcpy(s, "RetroActive", len);
          break;
-      case 3:
+      case XMB_ICON_THEME_PIXEL:
          strlcpy(s, "Pixel", len);
          break;
-      case 4:
+      case XMB_ICON_THEME_CUSTOM:
          strlcpy(s, "Custom", len);
          break;
    }

menu/drivers/xmb.c

@@ -314,15 +314,15 @@ const char *xmb_theme_ident(void)
    settings_t *settings = config_get_ptr();
    switch (settings->menu.xmb.theme)
    {
-      case 1:
+      case XMB_ICON_THEME_FLATUI:
          return "flatui";
-      case 2:
+      case XMB_ICON_THEME_RETROACTIVE:
          return "retroactive";
-      case 3:
+      case XMB_ICON_THEME_PIXEL:
          return "pixel";
-      case 4:
+      case XMB_ICON_THEME_CUSTOM:
          return "custom";
-      case 0:
+      case XMB_ICON_THEME_MONOCHROME:
       default:
          break;
    }

menu/menu_display.h

@@ -56,6 +56,15 @@ enum xmb_color_theme
    XMB_THEME_LAST
 };
 
+enum xmb_icon_theme
+{
+   XMB_ICON_THEME_MONOCHROME = 0,
+   XMB_ICON_THEME_FLATUI,
+   XMB_ICON_THEME_RETROACTIVE,
+   XMB_ICON_THEME_PIXEL,
+   XMB_ICON_THEME_CUSTOM
+};
+
 enum xmb_shader_pipeline
 {
    XMB_SHADER_PIPELINE_WALLPAPER = 0,

menu/menu_setting.c

@@ -6894,7 +6894,7 @@ static bool setting_append_list(
                   &settings->menu.xmb.theme,
                   msg_hash_to_str(MENU_ENUM_LABEL_XMB_THEME),
                   msg_hash_to_str(MENU_ENUM_LABEL_VALUE_XMB_THEME),
-                  xmb_theme,
+                  xmb_icon_theme,
                   &group_info,
                   &subgroup_info,
                   parent_group,