Use optnone instead, this does require a more recent clang though. In
general, just don't use -ffast-math.
Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
IANAL, but I think I am allowed to add missing copyright notices for
someone else. And I did my best job using git history to figure out who
wrote which functions. So I hope everything is fine.