Add TODOs for build changes

TODO.md

@@ -3,3 +3,5 @@
 - [x] ~~Add manual build steps to README.md~~
 - [x] Add OBS constraints file
     - [x] Set constraints for all the same as the overwrite for x86_64
+- [ ] Add all build dependencies from https://salsa.debian.org/mozilla-team/firefox/-/blob/release/master/debian/control
+- [ ] Test build override with mach as per https://git.savannah.gnu.org/cgit/gnuzilla.git/tree/data/buildscripts/build-gnulinux.sh