I am on a wilderness and DIY kick, work with me.
To make you own pitch glue you will need the sap from either a pine or fir tree. Gather the sap when it seeps from wounds, and heat it in a container to melt it. It will smell like turpentine, which is evaporating. Once the turpentine is gone, you will be left a thick rosin, once this has turned into a liquid, filter out any debris. This will be a thick glue like substance but to get it to dry you will need to add a handful of fine wood ash. Mix it when hot, use it when hot and use it quickly. It will only take a minute or so to harden.
Each glue will be different depending on what you are using. You can experiment with different items to see what works best for your situation.
To make glue using an animal hide, merely boil the scraps in a container, hard boil, the boiling will break down the hide, and you will need to add water now and then. Once the hide is broken down you are left with a water salable glue that is perfect for fixing things that need to be flexible.