d2bac19750
The `etc/virtual` file declares the default package to be built for virtual dependencies declared as "virtual?foo" in $depends. Before this change, the run-time dependency was added as is to the final binary package but no pkg providing this virtual pkg was built. With this file we declare the *default* pkg to be built. NOTE: "virtual?foo" is only applicable to *run* time dependencies, i.e only those declared in $depends.