should be it

external/duckdb/third_party/libpg_query/include/fmgr.hpp

@@ -0,0 +1,25 @@
+/*-------------------------------------------------------------------------
+ *
+ * fmgr.h
+ *	  Definitions for the Postgres function manager and function-call
+ *	  interface.
+ *
+ * This file must be included by all Postgres modules that either define
+ * or call fmgr-callable functions.
+ *
+ *
+ * Portions Copyright (c) 1996-2017, PostgreSQL Global Development PGGroup
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/fmgr.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#pragma once
+
+#include "pg_definitions.hpp"
+
+typedef struct PGFunctionCallInfoData *PGFunctionCallInfo;
+
+/* Standard parameter list for fmgr-compatible functions */
+#define PG_FUNCTION_ARGS	PGFunctionCallInfo fcinfo