SCons is listed as a meta build system here, but it is clearly an end-to-end build system. It seems to me SCons even fits all the requirements listed by the author. Plus, you program your SCons build using Python.
He also describes the dynamic discovery of header dependencies of Ninja as a hack. It is true that it is a special case to handle a specific type of dynamic dependencies. But the basic idea behind it (using the compiler's diagnostic as the source of truth) is sane and efficient. The alternative is to scan the sources using a custom parser, which is slower and more fragile.
Rust strings enforce utf-8 encoding, yes. However, it seems Windows (which uses utf-16) allows ill-formed UTF-16, in particular it tolerates unpaired surrogates.
He also describes the dynamic discovery of header dependencies of Ninja as a hack. It is true that it is a special case to handle a specific type of dynamic dependencies. But the basic idea behind it (using the compiler's diagnostic as the source of truth) is sane and efficient. The alternative is to scan the sources using a custom parser, which is slower and more fragile.