Only enable cmake response files on windows (#26312)

This matches GCC and Clang do on in upstream/native CMake toolchains do:

```
Modules/Platform/Emscripten-Clang.cmake:  set(CMAKE_${lang}_USE_RESPONSE_FILE_FOR_INCLUDES 1)
Modules/Platform/Windows-Clang.cmake:  set(CMAKE_${lang}_USE_RESPONSE_FILE_FOR_INCLUDES 1)
Modules/Platform/Windows-Embarcadero.cmake:  set(CMAKE_${lang}_USE_RESPONSE_FILE_FOR_INCLUDES 1)
Modules/Platform/Windows-GNU.cmake:  set(CMAKE_${lang}_USE_RESPONSE_FILE_FOR_INCLUDES 1)
```

i.e. GCC and Clang don't use these settings except on windows.

Author: sbc100

cmake/Modules/Platform/Emscripten.cmake

@@ -268,12 +268,15 @@ endif()
 
 set(CMAKE_EXECUTABLE_SUFFIX ".js")
 
-set(CMAKE_C_USE_RESPONSE_FILE_FOR_LIBRARIES 1)
-set(CMAKE_CXX_USE_RESPONSE_FILE_FOR_LIBRARIES 1)
-set(CMAKE_C_USE_RESPONSE_FILE_FOR_OBJECTS 1)
-set(CMAKE_CXX_USE_RESPONSE_FILE_FOR_OBJECTS 1)
-set(CMAKE_C_USE_RESPONSE_FILE_FOR_INCLUDES 1)
-set(CMAKE_CXX_USE_RESPONSE_FILE_FOR_INCLUDES 1)
+if (CMAKE_HOST_WIN32)
+  # See https://github.com/emscripten-core/emscripten/issues/2386
+  set(CMAKE_C_USE_RESPONSE_FILE_FOR_LIBRARIES 1)
+  set(CMAKE_CXX_USE_RESPONSE_FILE_FOR_LIBRARIES 1)
+  set(CMAKE_C_USE_RESPONSE_FILE_FOR_OBJECTS 1)
+  set(CMAKE_CXX_USE_RESPONSE_FILE_FOR_OBJECTS 1)
+  set(CMAKE_C_USE_RESPONSE_FILE_FOR_INCLUDES 1)
+  set(CMAKE_CXX_USE_RESPONSE_FILE_FOR_INCLUDES 1)
+endif()
 
 set(CMAKE_C_RESPONSE_FILE_LINK_FLAG "@")
 set(CMAKE_CXX_RESPONSE_FILE_LINK_FLAG "@")