Security warnings when using LLVM 9

[uxio prego]

Dear maintainer,
I bet you already know that Bison... 2.7 up to... 3.1 I think?
Can output a PREFIX.tab.c doc so that when compiled by
LLVM 9 a security warning (see `man 3 printf`) gets
emitted.

I don't know much about LLVM, but I think they claim to be
GCC compatible. Does Bison in any way claim to be LLVM
compatible?

Were you aware of such LLVM alerts? Do you want me to
share my compiler warnings?

Thank you very much in advance,
cheerfully yours,

Sent from my iPad