Coverity does not like the new _Float* types that are used by
recent glibc, and croaks on every single file that includes
stdlib.h. Add dummy typedefs to please it.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>