I mean, so long as you're willing to take a build-dep on that, in that case.

Just a c compiler.

No. So long as you're willing to take a build-dep on that code.

Either you're expecting the code from that repository to exist somewhere in the compilation-host system already, or you are vendoring the code by copying it into your own repository and taking on any potential maintenance, unportability, any necessary configuration integration to make sure, for instance, that you're compiling for the host rather than the target in a cross-compile setup (did you make sure?)—

Either way, if you use that code as part of your build process, you are taking a build-dep on that code. The fact that its only build-dep is a C compiler may play into making this a sensible choice as compared with something that has even more transitive dependencies, but it does not make it go away.