On platforms like Linux, we need to build crt prior building the rest of
compiler-rt. This change introduces support for building crt with the
bootstrapping build akin to builtins.
I might be missing it, but I don't see crt depending on builtins (or vice versa). If there is actually no dep, could we build them together in a single configure, instead of needing to add another one for crt? If there is a dep and I missed it, then this LGTM.
There is no dependency because crt and builtins aren't dependent on each other. We could build them in a single configure, but we would another top level CMakeLists.txt. Do you have any suggestions for where that should live?
Sorry, this fell off my radar. This is fine as-is; avoiding the extra configure could potentially be nice for build times, but we can address that later if it's actually an issue. I don't have a great idea for the placement of the combined builtins+crt CMakeLists.