xmagic
offsetof(Pkg, Pkgn.iob[FILE_ARY_SZ-1].xmagic) &&
offsetof(Pkg, Pkgn.iob[0].xmagic)) {
xfp[i].xmagic = XMAGIC(&xfp[i]);
(((uintptr_t)&(xfp)->xmagic & 0xfff) && \
(xfp)->xmagic == XMAGIC(FILEx(xfp)))