Comment by WhiteNoiz3

There are a few.. Zig compiles to webassembly and looks fairly C-like. You can also use Cheerp or Emscripten to compile C to WebAssembly (though they both assume you are targeting the browser).

Also +1 for Assemblyscript which is fairly C-ish. It's based on Javascript / Typescript but really works more like C if you are doing anything low level (also it doesn't support Closures etc).