Per [1], Zig seems to have its own C compiler (AFAICT it's not just a frontend to an existing one)
[1] https://andrewkelley.me/post/zig-cc-powerful-drop-in-replace...
[1] https://andrewkelley.me/post/zig-cc-powerful-drop-in-replace...
I'm not sure what the current plan is for C compilation after the LLVM divorce and after Clang will be moved into a Zig package (e.g. I remember talk that arocc [1] is going to be integrated into the Zig compiler, but not sure if that's still planned, or if C compilation will also be delegated to the new Clang package along with C++ and ObjC compilation).