[Bug c/70742] Support div as a builtin

[daniel.gutson at tallertechnologies dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70742

--- Comment #2 from Daniel Gutson <daniel.gutson at tallertechnologies dot com> ---
(In reply to Andrew Pinski from comment #1)
> Let me reword the summary.  what you want is div and ldiv and imaxdiv to be
> supported as a builtin, in that it expands correctly to do the div/mod
> inlined.
> 
> >The goal is that std::div and cstdlib's div can be reimplemented as calling this builtin.
> 
> Or rather they stay the way they are and GCC rewrites it to be correct.  AKA
> no reimplementing at all.

That's correct, my bad: the goal is actually not touching the library at all.