Build stage2 cross compilers
The main payload of this patch is to properly package cross compilers as stage2 compilers like a normal compiler.
There are many advantages to this from a packaging perspective:
- Uniformity with existing builds means that the same build flavours and workflows work when building cross compilers.
- The compiler we distribute is built against the in-tree runtime.
- Cross compilers are packaged to bindists, the bindists are installed and tested (like normal compilers).
This also opens up the way for building and testing stage3 compilers, which are native compilers for the target built by the cross compiler.
Edited by Matthew Pickering