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

[schwab--- via Gcc-bugs]

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

--- Comment #10 from Andreas Schwab <sch...@linux-m68k.org> ---
That doesn't fix anything.

https://build.opensuse.org/project/monitor/home:Andreas_Schwab:riscv:gcc