Real build systems need to deal with any language. Cargo is a negative on large projects because it has opinions that make things easy for small rust only projects and falls flat on complex projects-
good build systems need to bea real programming language. The more declaritive the better - this is different from the project that often should be a different style
As long as the build system can run external programs, you're really not limited to a single language (or even compiling source code). In the end build systems are just fancy task runners, no matter if they are integrated with a language toolchain or separate products.
Sortof. If the build system doesn't understand the dependencies you have inefficient builds as it can't schedule all cores effectively at all times. On a large complex project this matters
good build systems need to bea real programming language. The more declaritive the better - this is different from the project that often should be a different style