[PATCH v4 2/2] stdio-common: Fix buffer overflow in scanf %mc [BZ #34008]

[Rocket Ma]

> If the function need to be separated, then the old behavior, "size_t
> newsize = strsize + (strsize >= width ? width : strsize)", is not
> worth a new function. And the function only expands to several
> instructions, less than 10, observed via Compiler Explorer. I think
> it's OK to inline the function.
>
> Since the behavior mentioned has become some sort of convention, the
> function should be OK? Readers has the constant to distinguish between
> %ms and %mc, and they can understand the code via enough comments.
> Personally I think it's worth to put these two actions together to do
> one thing: calculate the size of expanded array.

Any idea?