Single threaded concurrency for emscripten

[Umenokin]

From coro's CMakeLists.txt it seems libcoro forcing pthread flags:

if(DEFINED EMSCRIPTEN)
    add_compile_options(-fwasm-exceptions)
    add_compile_options(-pthread)
    add_compile_options(-matomics)

    add_link_options(-fwasm-exceptions)
    add_link_options(-pthread)
    add_link_options(-sPROXY_TO_PTHREAD)
    add_link_options(-sALLOW_MEMORY_GROWTH)
    add_link_options(-sEXIT_RUNTIME)
endif()

But why not supporting single threaded builds? It seems there are certain performance constrains using web workers for threads and many projects still using single threaded builds. I was checking taskflow and libcoro. Generally either would've work for my case but single threaded concurrency felt like strong advantage, especially for wasm builds

[jbaldwin]

I just hadn't considered it, if you know the correct settings and would like to open a PR to add this feature I think it would be a good addition to the emscripten build!

[Umenokin]

@jbaldwin I will try. I am actually complete nub Emscripten and CMake last time using C++ 15 years ago.
I will try addressing my current issue one by one and than try playing around with libcoro wasm config once confirm the I have concurrent stack natively. Thanks a lot for all your help!