Vendor dependencies

Let's see how I like this workflow.

vendor/cxx-build/src/gen/names.rs

@@ -0,0 +1,14 @@
+use crate::syntax::Pair;
+
+impl Pair {
+    pub fn to_fully_qualified(&self) -> String {
+        let mut fully_qualified = String::new();
+        for segment in &self.namespace {
+            fully_qualified += "::";
+            fully_qualified += &segment.to_string();
+        }
+        fully_qualified += "::";
+        fully_qualified += &self.cxx.to_string();
+        fully_qualified
+    }
+}