Add activity for evaluation

src/libutil/logging.hh

@@ -20,6 +20,7 @@ typedef enum {
     actQueryPathInfo = 109,
     actPostBuildHook = 110,
     actBuildWaiting = 111,
+    actEvaluate = 112,
 } ActivityType;
 
 typedef enum {

src/nix/installables.cc

@@ -356,6 +356,8 @@ struct InstallableStorePath : Installable
 
 Buildables InstallableValue::toBuildables()
 {
+    Activity act(*logger, lvlInfo, actEvaluate);
+
     Buildables res;
 
     std::map<StorePath, std::map<std::string, std::optional<StorePath>>> drvsToOutputs;