Whenever declare_dependency is used to add some compile flags or dependent
libraries to the outcome of dependency(), the version of the original
dependency is dropped in the summary.  Make sure that declare_dependency()
has a version argument in those cases.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>