I already knew that Ninja only supports a limited subset and that the issue is the compiler now going beyond that limited subset. My point is that I wouldn't j

I already knew that Ninja only supports a limited subset and that the issue is the compiler now going beyond that limited subset. My point is that I wouldn't jump to conclusions as to why they did that. I would dig further to see what the reasons were (which is not a simple google search) and what Ninja developers could do about that. Another important point is that they didn't break Ninja compatibility in general, but only in the specific case of C++ modules; and they also didn't break compatibility with non-GNU implementations of Make.