https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123987
--- Comment #12 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
We can expand isinf{f,l} according to BSD semantics in a BSD-targeting
compiler, sure. But the functions are not defined by C or POSIX, so expanding
them that way when targeting GNU libc makes it a GCC bug, no?
