Only include editor/SCsub when building the editor: tools=yes

(cherry picked from commit 2efe9a89bb2b352c50429b7bb3c1accafc8662d1)

SConstruct

@@ -679,7 +679,8 @@ if selected_platform in platform_list:
     SConscript("core/SCsub")
     SConscript("servers/SCsub")
     SConscript("scene/SCsub")
-    SConscript("editor/SCsub")
+    if env["tools"]:
+        SConscript("editor/SCsub")
     SConscript("drivers/SCsub")
 
     SConscript("platform/SCsub")