[Bug c/89072] -Wall -Werror should be defaults

[vincent-gcc at vinc17 dot net via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89072
--- Comment #6 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> ---
BTW, note that some code may be generated (instead of being written by a
human). So having some code style being an error by default would be very bad.