Or just rewrite it in modern C. This is sane and doable in a short period of time. You just have to make sure it's modern C.
(no true Scotsman)
(no true Scotsman)
What do you call modern C?
"We found a terrifying vulnerability in your codebase. You should rewrite it in modern C++."
"OK, done!"
<Time passes>
"We found a terrifying vulnerability in your codebase. It must not have been modern C++!"