gistfile1.txt

#include "postgres.h"

#include "fmgr.h"
#include "utils/guc.h"

PG_MODULE_MAGIC;

void _PG_init(void);

static char *query_group = NULL;

/*
 * Module load callback
 */
void
_PG_init(void)
{
	/* Define custom GUC variables. */
	DefineCustomStringVariable("query_group",
							"Redshift compatibility, ignored.",
							NULL,
							&query_group,
							"",
							PGC_USERSET,
							0,
							NULL,
							NULL,
							NULL);
}

gistfile2.txt

MODULE_big = guchack

OBJS = guchack.o

PG_CONFIG = pg_config
PGXS = $(shell $(PG_CONFIG) --pgxs)
include $(PGXS)