>>> C is itself a massive dependency
the C standard library?
No, the C compiler. Both gcc and Clang are pretty big, even before you account for the standard library. I suppose you could get away with something like tcc, though.
the C standard library?
This matters more for distros and OSes where building things from source - either everything, as in e.g. Gentoo, or at least the base system, as in the BSDs - is pretty common and expected.