verilator_process_wrapper not returning correct exit code

[benreynwar]

When verilator fails to compile the return value is sometimes incorrect, causing bazel to think it was successfull when it wasn't.

Currently it does (see verilator/private/verilator_process_wrapper.cc)

int result = std::system(cmd.c_str());
if (result != 0) {
  return result;
}

but std::system doesn't return the exit code. Running on ubuntu it returns exit_code << 8 for me, so a 1 becomes 256 which bazel then helpfully converts to 0.

I'm now using

if (result != 0) {
        if (WIFEXITED(result)) {
            int exit_code = WEXITSTATUS(result);
            return exit_code;
        } else {
            return 1; // Process was terminated by signal
        }
    }

and it works, but I have no idea whether this is a portable solution.