[compiler-rt] r211035 - builtins: add it blocks for Thumb-2

[Tim Northover]

Hi Saleem,

Just noticed something odd about this patch:

> +       IT cc
>         bcc     LOCAL_LABEL(divby0)

Conditional branches don't generally need an IT instruction. Certain
branches can work with them, but almost certainly with an inferior
encoding.

Cheers.

Tim.