message: Fix __u_long to size_t in C API
diff: @@ -1322,8 +1322,8 @@ mod tests {
  long CustomWasiStdin_destructor(
  const void* env,
  - __u_long sz,
  - __u_long ao
  + size_t sz,
  + size_t ao
  ) {
  (void)env;
  (void)sz;
  @@ -1333,9 +1333,9 @@ mod tests {
  long CustomWasiStdin_onStdIn(
  const void* env,
  - __u_long sz,
  - __u_long ao,
  - __u_long maxwrite,
  + size_t sz,
  + size_t ao,
  + size_t maxwrite,
  wasi_console_stdin_response_t* in
  ) {
  CustomWasiStdin* ptr = (CustomWasiStdin*)env;
  