Preheat oven to 425°. Arrange turkey neck and giblets in a large ovenproof skillet. Roast until very well browned, 35–40 minutes. Remove from oven, add wine, and set over medium heat. Cook, scraping up any browned bits, until wine is reduced by three-quarters, 8–10 minutes. Transfer neck, giblets, and liquid to a large pot; add chicken wings, onion, garlic, and 8 cups water. Bring to a boil, reduce heat, and simmer until liquid is reduced to about 3 cups, about 1 hour. Strain stock through a fine-mesh sieve into a large bowl; discard solids.