Sorry, if problem is not relatable to the OS. I have libstdc++ installed, swupd repair checks passes, but coroutines header not present neither in experimental, nor in standard include. What additional bundle should I install? Or are there any other ways to use coroutines?
header files are in devpkg- bundles. Try looking in sudo swupd bundle-list --all.
Headers are present now, after the main compilers were updated to the latest release. Thanks for your answer!