Are you sure about that? When I configure with -Wall -Werror, I can't even configure properly; one gets the errors
configure: libxrandr development files not found, XRandr won't be supported. configure: libxinerama development files not found, multi-monitor setups won't be supported. configure: WARNING: Old Mesa headers detected. Consider upgrading your Mesa libraries. OpenGL and Direct3D won't be supported.
This is precisely part of the problem with -Werror. You've now caused some configure checks to fail that, presumably, were passing before. Are they worth making warning-free? Some of the warnings may be in headers we don't control. What do we do then?
And if one blows past those, "make depend" fails. In fact, everything fails pretty spectacularly.
So a broken config leads to a broken compile? I guess I'm not seeing the severity of that. --Juan