We will be needing to use these helpers between the user and softmmu
files so declare them in the headers, add a system prefix and remove
static from the implementations.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

Message-Id: <20230302190846.2593720-10-alex.bennee@linaro.org>
Message-Id: <20230303025805.625589-10-richard.henderson@linaro.org>