8a2bd74787
The macOS catalina compiler produces an error for __int128_t as the type for allocation with SSE inline asm constraint. Create a new X86Int128Union type and use the vector type for all SSE register inputs and outputs. Tested-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>