Move const PortName data out of header file

mojo/edk/system/ports/name.h

Index: mojo/edk/system/ports/name.h
diff --git a/mojo/edk/system/ports/name.h b/mojo/edk/system/ports/name.h
index 1082719f6df5f29c37d3a6bb6df00fc8a78514fd..72e41b92ab68a2ddad163848da7719c2e4ce4522 100644
--- a/mojo/edk/system/ports/name.h
+++ b/mojo/edk/system/ports/name.h
@@ -40,14 +40,14 @@ struct PortName : Name {
   PortName(uint64_t v1, uint64_t v2) : Name(v1, v2) {}
 };
 
-const PortName kInvalidPortName = {0, 0};
+extern const PortName kInvalidPortName;
 
 struct NodeName : Name {
   NodeName() : Name(0, 0) {}
   NodeName(uint64_t v1, uint64_t v2) : Name(v1, v2) {}
 };
 
-const NodeName kInvalidNodeName = {0, 0};
+extern const NodeName kInvalidNodeName;
 
 }  // namespace ports
 }  // namespace edk