[Bug c/108896] provide "element_count" attribute to give more context to __builtin_dynamic_object_size() and -fsanitize=bounds

[muecker at gwdg dot de via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896

--- Comment #48 from Martin Uecker <muecker at gwdg dot de> ---
Indicating a null terminated string should certainly use a different attribute
name.