https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88695
--- Comment #5 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- It's DR#316 that's relevant here (where the committee agreed with my interpretation that implies this example is valid, and reiterated their intent not to fix issues with unprototyped functions in the standard), not DR#317.
