Bug#996802: llvm-toolchain-12: FTBFS on s390x since 1:12.0.1-10: Cannot find builtins library for the target architecture

[Simon McVittie]

Control: retitle -1 llvm-toolchain-12: FTBFS on s390x since 1:12.0.1-10: Cannot find builtins library for the target architecture
Control: found -1 1:12.0.1-13

On Thu, 21 Oct 2021 at 10:19:01 +0100, Simon McVittie wrote:
> 1:12.0.1-11 has a similar issue on armhf, presumably exposed by fixing
> #996828.

This appears to be fixed in 1:12.0.1-13 on armhf, but s390x still has
the same issue.

After llvm-toolchain-12 in unstable gets back to a state where all release
architectures are built successfully, I think it would be better to use
experimental to try different ways of building, and only upload to unstable
when all release architectures work - otherwise it's disruptive to packages
like Mesa (and, indirectly, many GUI programs).

    smcv