https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92292
--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- This would be an interaction between the built-in function having a printf format attribute and the header having either a gnu_printf or an ms_printf format attribute (depending on feature test macros); as those attributes aren't exact duplicates, both are applied (it's perfectly valid for a function to have multiple format attributes, but I suppose we should special-case this for format attributes for built-in functions with a more specific format attribute in the header declaration).
