[C++ coroutines] Initial implementation pushed to master.

[Jakub Jelinek]

On Sat, Jan 18, 2020 at 12:53:48PM +0000, Iain Sandoe wrote:
Thanks.

Shouldn't this be mentioned in https://gcc.gnu.org/projects/cxx-status.html
?

> * This is not enabled by default (even for -std=c++2a), it needs -fcoroutines.

And, if this is the planned case even for GCC 10 release, I think the
-fcoroutines option needs to be mentioned there too.

	Jakub