Add new JSON_USE_NULLREF flag
This patch adds a new flag, JSON_USE_NULLREF, which removes
the legacy singletons null, nullRef for consumers that require not
having static initialized globals, like Chromium.
diff --git a/include/json/config.h b/include/json/config.h
index eca9e8c..8724ad9 100644
--- a/include/json/config.h
+++ b/include/json/config.h
@@ -30,6 +30,11 @@
#define JSON_USE_EXCEPTION 1
#endif
+// Temporary, tracked for removal with issue #982.
+#ifndef JSON_USE_NULLREF
+#define JSON_USE_NULLREF 1
+#endif
+
/// If defined, indicates that the source file is amalgamated
/// to prevent private header inclusion.
/// Remarks: it is automatically defined in the generated amalgamated header.