Without extra flags, we would try to use LLVM 13 for cgo and LLVM 14 for
other things since 873412b43a. That isn't
great. So fix this by only using LLVM 14 in the cgo package.
Switch over to LLVM 14 for static builds. Keep using LLVM 13 for regular
builds for now.
This uses a branch of the upstream Espressif branch to fix an issue,
see: https://github.com/espressif/llvm-project/pull/59
