Compiler is not EMSCRIPTEN

Hi, I‘m using Ubuntu 22.04. and I put my **emsdk** under folder `/opt/emsdk`.
However, I got the following **ERROR** message. ` Compiler is not EMSRIPOM`

```console
-- Compiler is not EMSCRIPTEN
CMake Deprecation Warning at build/_deps/brotli-src/CMakeLists.txt:5 (cmake_minimum_required):
Compatibility with CMake < 2.8.12 will be removed from a future version of
CMake.

Update the VERSION argument value or use a ... suffix to tell
CMake that the project does not need compatibility with older versions.

Build type is 'Release'
-- Compiler is not EMSCRIPTEN
Configuring done (0.4s)
```

Can anybody give me a hand? Thank you ..