The symbol is always defined, even if to 0. We wanted to test for TCG_OVERSIZED_GUEST == 0. This fixed, the #error is reached while building arm-softmmu, because TCG_OVERSIZED_GUEST is not true (nor supposed to be true) for arm32 guest on a 32-bit host. But that's ok, because this feature doesn't apply to arm32. Add an #ifdef for TARGET_AARCH64. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>