message: Fix defines for emscripten
diff: @@ -40,7 +40,11 @@ limitations under the License.
  #elif defined(_WIN32)
  #define PLATFORM_WINDOWS
  -#elif defined(__arm__) || defined(__EMSCRIPTEN__)
  +#elif defined(__arm__)
  +#define PLATFORM_POSIX
  +
  +#elif defined(__EMSCRIPTEN__)
  +#define PLATFORM_PORTABLE_GOOGLE
  #define PLATFORM_POSIX
  // Require an outside macro to tell us if we're building for Raspberry Pi or
  