I spun up a Linux VM for testing.
I installed build-essential.
Now I believe I need my game's SDK, MM source and SM source. But I'm lost trying to figure out how to download the TF2 SDK. Google tells me to grab the Source 2013 SDK, but that doesn't appear to be correct and I'm hearing that each game's SDK was spun off.
There is this Git repository where there is a TF2 tree, but if I clone the repo I get the whole repo and not necessarily the TF2 tree.