move _PG_* declarations to mod.h

cstore.h

@@ -266,10 +266,6 @@ typedef struct TableWriteState
 
 } TableWriteState;
 
-/* Function declarations for extension loading and unloading */
-extern void _PG_init(void);
-extern void _PG_fini(void);
-
 extern CompressionType ParseCompressionType(const char *compressionTypeString);
 extern void InitializeCStoreTableFile(Oid relationId, Relation relation,
 									  CStoreOptions *cstoreOptions);

mod.c

@@ -13,6 +13,7 @@
 
 #include "postgres.h"
 
+#include "mod.h"
 #include "cstore_fdw.h"
 
 PG_MODULE_MAGIC;

mod.h

@@ -0,0 +1,21 @@
+/*-------------------------------------------------------------------------
+ *
+ * mod.h
+ *
+ * Type and function declarations for CStore
+ *
+ * Copyright (c) 2016, Citus Data, Inc.
+ *
+ * $Id$
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef MOD_H
+#define MOD_H
+
+/* Function declarations for extension loading and unloading */
+extern void _PG_init(void);
+extern void _PG_fini(void);
+
+#endif /* MOD_H */