Uses the MinGWClangCross toolchain script to build yuzu. Disables our
bundled SDL2 to use the system ones that have been modified to not use
`-mwindows`. Also set's `-e` to stop the script on an error (as opposed
to packaging nothing).

Uses LLVM's linker for linking yuzu. Adds -femulated-tls due to a
libstdc++ incompatibility between GCC and Clang in vulkan_common.