OK Gluten free living in Uganda is easy. Simply because wheat is not mass produced here. People eat maize and millet as their staple so you don't have to worry about wheat creaping in as a thickener. Curry powder has cereals written on label but that means corn not wheat.
If you are in Kampala you can pick up corn crackers, rice pasta and cereal that is gluten free at a south African shop called Game or Shoprite. Also a Kenyan company called Nakumat is in Kampala in Garden city mall, ive never been there but you can assume they'd have some nice products.
On a more localized note if you are in Jinja town then check out Indulge they can make a delicious gluten free brownie. I was shocked when I found it and even more shocked at how amazingly moist it is. They can also make the brownie into a cake if a party is on your agenda. Other than that most food around is gluten free so no worries if you must live in Uganda.