[Bug target/106529] existence of sincos is assumed

[tk at giga dot or.at via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106529

--- Comment #5 from Thomas Klausner <tk at giga dot or.at> ---
For context, I stumbled over this because meson misdetects sincos on NetBSD.

https://github.com/mesonbuild/meson/issues/10641