message: Update lib/c-api/tests/wasmer_wasm.h
diff: // This header file is used only for test purposes! It is used by unit
  // test inside the `src/` directory for the moment.
  -#if !defined(TEST_WASMER_WASM)
  -
  +#ifndef TEST_WASMER_WASM
  #define TEST_WASMER_WASM
  #include <string.h>
  