Add -Werror for meson CI build
This enables -Werror
in the fedora CI build to ensure that new warnings do not creep in. I've added a -Wno-error=deprecated-declarations
exception because we still have a few deprecated-declarations warnings and even once these warnings are fixed, I don't want the build to break the next time the build dependencies are updated in CI.
Also includes some GL warnings fixes that I did not notice last time I was attempting to eliminate all warnings but -Werror certainly did.