Looks like boringssl will need some patches as well or needs to be compiled without -Werror.

The only remaining problem now seems to be that CMAKE_C_FLAGS and CMAKE_CXX_FLAGS set in vendor/boringssl/CMakeLists.txt are overwritten with the values set in vendor/CMakeLists.txt which causes a boringssl compile error on Arch Linux with clang/clang++. Not entirely sure why this is happening as it works on Alpine locally with the same CMake version.