I, personally, think it's time to get over the expectation that it's realistic to use c++ without a build system.
Especially in teaching context, we should prepare folks to the real world, which necessarily involves a build system, instead of creating this anachronistic requirements.
It is important for programmers, especially for C++, to understand the entire pipeline that they use. Relying on tools, like build systems and IDEs, hiding the knowledge makes for inefficient programmers. Learning that pipeline starts at invoking the compiler directly.