support @same for dependency references

this allows us to uniformly use the same value in all branches, which
simplifies merging.

Change-Id: I278617762c169814697b49f29b5e363c7a3901f9
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@digia.com>