Add more standard c lib llvm intrinsics.

[luqmana]

Expose some of the available llvm intrinsics to rust. Perhaps could use them in place of calls to libm.

[brson]

Thanks!

Sorry to inconvenience you but Rust is in the process of switching to a dual MIT/ASL2 license, a fact which is not yet reflected in the Rust LICENSE file. As such I need to confirm that you consent to this license.

ASL2 is a permissive license with a patent non-aggression clause. The details are here.

If you agree just say 'I agree to license this code under the terms of MIT/ASL2'.

[brson]

I guess there's no harm in doing this and somebody will need some of them eventually, though we have typically only added intrinsics as needed. Do you have a use case you need some of these for?

[luqmana]

Ah, I've already responded in Graydon's email (i'm fine with the relicensing).

One specific use case I was thinking of was the lmath library. They also could possibly be used in the cmath lib.

[brson]

Merged. Thanks.