rmm: [BUG] RMM spits pages of deprecated warnings when building

Describe the bug and steps to reproduce

mkdir build && cd build
cmake .. # options
make -j

outputs pages of deprecated warnings due to the use of [[deprecated]] APIs in tests.

I can reproduce this with clang and gcc.

Expected behavior

The current development branch builds without warnings. Otherwise I need to skim through pages of warnings every time I make a change to verify that I haven’t introduced any new issues, which costs me time.

Environment details (please complete the following information):

• Environment location: docker
• Method of RMM install: source
• Docker: custom image, no docker pull provided.

Other

Possible fix: always test simple build without dependencies on CI, using -Werror to prevent this issue from being re-introduced in the future.