GCC 12 (unlike GCC 9) does not match a function argument passed to the
old qsort_r() API (as is used in the qsort_r_compat test) to a
function pointer type via __generic. It treats the function type as a
distinct type from a function pointer. As a workaround, add a second
__generic() condition which matches on the function type that also
falls back to __qsort_r_compat.