We already have GCC, but ada language support is not enabled.
I managed to bootstrap it. I will provide a link to binary packages soon. For now I have the package.yml files that I used for the bootstrap.
It appears that gcc-ada is required for Intel graphics to work on most boards when compiling CoreBoot.
So I had found when attempting to compile CoreBoot (for the first time) for my grandmother's old computer (apparently it is almost completely supported, with just a few things left which are merely untested), after building for her a new computer (AMD B450-based).
I'm still trying to get to the root of this, however it seems that there is an issue compiling the x86-64 crosschain for GCC 8 (no idea why this is what is needed for Coreboot, at least the Dasharo implementation for the Optiplex 7010/9010) that comes from the gcc-ada headers.