Use glGenQueries failure with Emscripten in Web
When I use glfw3 + glad2.0 to transpile my C++ code to WebAssembly, everything works well. I choose the gles2 version3.2 core, and I can render a triangle in the newest version of Microsoft Edge browser with WebGL2.

Here are some code snippets for my CMakeLists.txt
```
# I write the CMakeLists for the glad
target_link_libraries(${PROJECT_NAME} PRIVATE glad)

if (EMSCRIPTEN)
    target_link_libraries(${PROJECT_NAME} PRIVATE "-s USE_GLFW=3")
    target_link_libraries(${PROJECT_NAME} PRIVATE "-s FULL_ES3=1")
    target_link_libraries(${PROJECT_NAME} PRIVATE "-s MIN_WEBGL_VERSION=2")
    target_link_libraries(${PROJECT_NAME} PRIVATE "-s MAX_WEBGL_VERSION=2")
    target_link_libraries(${PROJECT_NAME} PRIVATE "-s WASM=1")
    target_link_libraries(${PROJECT_NAME} PRIVATE "-s NO_DISABLE_EXCEPTION_CATCHING=1")
    target_link_libraries(${PROJECT_NAME} PRIVATE "-s ALLOW_MEMORY_GROWTH=1")
    target_link_libraries(${PROJECT_NAME} PRIVATE "-s GL_SUPPORT_AUTOMATIC_ENABLE_EXTENSIONS=1")
else()
    target_link_libraries(${PROJECT_NAME} PRIVATE glfw)
endif()
```

However, when I want to use glGenQueries to test GL_ANY_SAMPLES_PASSED, so as to perform order independent transparency rendering, I encounter a problem.

The browser tells me GLctx.disjointTimerQueryExt.createQueryEXT is not a function.

I search for MDN and it tells me that in WebGL2, the function is changed into GLctx.createQuery.
[EXT_disjoint_timer_query](https://developer.mozilla.org/en-US/docs/Web/API/EXT_disjoint_timer_query)
[createQuery](https://developer.mozilla.org/en-US/docs/Web/API/WebGL2RenderingContext/createQuery)

I only include the header from glad, i.e. glad/gles2.h, while not including any OpenGL/ES header file from Emscripten.

Is it a problem with glad or it's a problem with Emscripten?

By  the way, I also tried to replace the original glad library with gles2.0 compatible + GL_EXT_disjoint_timer_query. It didn't work either.

Thanks in advance.