[Bug target/110812] Check availability of builtins at expand time

[kito at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110812

--- Comment #30 from Kito Cheng <kito at gcc dot gnu.org> ---
Yes, I plan port that to GCC 15 branch, I am just wait one week as the
convention to make sure the patch is stable enough :)