Compiling lexical_cast to an integer from a char with gcc and -O3 results in "array subscript -1 is outside array bounds" warnings

Starting with boost 1.85, when compiling the following code ([Godbolt](https://godbolt.org/z/q7c5jK799))
``` cpp
#include
int f(char n) {
return boost::lexical_cast(n);
}
```
`gcc -O3 -Wall -Wextra -pedantic` produces scary-looking warnings `array subscript -1 is outside array bounds`.