Transfer the turkey from the roasting pan and place on a platter to rest, tented with aluminum foil.
Pour the reserved turkey pan juices into a glass measuring cup and skim off the fat. Place the roasting pan on two stovetop burners over medium heat. Add1 cup turkey broth and the white wine to the pan, and deglaze the pan, stirring to scrape any brown bits from the bottom of the pan. Add the remaining 3 cup of broth and bring to a simmer, then transfer to a pot or measuring cup.
In a large heavy saucepan, melt the butter over medium high heat. Stir in the flour and cook, stirring constantly, to make a light roux. Add the hot stock, whisking constantly, then simmer until thickened, about 10 minutes. Add the reserved neck meat and giblets to the pan and adjust seasoning to taste with salt and black pepper. Pour into a gravy boat and serve.