Migrate machine and hostname identification from fishd.cpp to

env_universal_common.cpp, so that fish can use it

env_universal.cpp

@@ -495,3 +495,14 @@ void env_universal_get_names(wcstring_list_t &lst,
                                    show_exported,
                                    show_unexported);
 }
+
+
+bool synchronizes_via_fishd()
+{
+    if (program_name && ! wcscmp(program_name, L"fishd"))
+    {
+        /* fishd always wants to use fishd */
+        return true;
+    }
+    return false;
+}