[Bug libstdc++/99338] -f and -l variants of cmath functions missing (e.g. std::cosf() and std::cosl())

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99338

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
As I said in bug 79700, their existence prior to C++17 was underspecified. They
were never mentioned in the previous standards.