handler_config: Split out from buildjson

This allows us to build the version-handler without the json
infrastructure.

Change-Id: I8c0a5715cb66f6cbb3e72cb714759f6e11e3f409
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/bmc/version-handler/version_handler.cpp b/bmc/version-handler/version_handler.cpp
index 7cccf62..f2ab881 100644
--- a/bmc/version-handler/version_handler.cpp
+++ b/bmc/version-handler/version_handler.cpp
@@ -1,5 +1,11 @@
 #include "version_handler.hpp"
 
+#include <algorithm>
+#include <cstring>
+#include <ios>
+#include <limits>
+#include <memory>
+#include <optional>
 #include <utility>
 #include <vector>