Example libpq program fails when built with mingw ld-2.15.91 on WinXP (but not ld-2.13.90)

I have a slightly modified version of one of the example C programs
from the help docs. When built with gcc-3.4.2/ld-2.13.90 under MingW
on WinXP it works as expected. When linked with ld-2.15.91 (or later;
same gcc) it segfaults on the first call to PGprepare. Does anyone
else have this problem, or can you reproduce?

Alistair

File: test.c

#include <stdio.h>
#include <stdlib.h>
#include "libpq-fe.h"

static void exit_nicely(PGconn *conn)
{   PQfinish(conn);   exit(1);
}

void check_error(PGconn *conn, PGresult *res, ExecStatusType rc, char *msg)
{   if (PQresultStatus(res) != rc)   {       /* fprintf(stderr, msg, PQerrorMessage(conn)); */       fprintf(stderr,
"%s:%s\n", msg, PQerrorMessage(conn));       PQclear(res);       exit_nicely(conn);   } 
}

int main(int argc, char **argv)
{   const char *conninfo;   PGconn     *conn;   PGresult   *res;   int         nFields;   int         i,
j;      Oid paramTypes[10]; 
   /*    * If the user supplies a parameter on the command line, use it as the    * conninfo string; otherwise default
tosetting dbname=postgres and using    * environment variables or defaults for all other connection parameters.    */
if(argc > 1)       conninfo = argv[1];   else       conninfo = "dbname = postgres"; 
   /* Make a connection to the database */   conn = PQconnectdb(conninfo);
   /* Check to see that the backend connection was successfully made */   if (PQstatus(conn) != CONNECTION_OK)   {
fprintf(stderr, "Connection to database failed: %s", 
PQerrorMessage(conn));       exit_nicely(conn);   }
   /* my test case... */   res = PQprepare(conn, "x", "DECLARE myportal CURSOR FOR select *
from pg_database", 0, paramTypes);   check_error(conn, res, PGRES_COMMAND_OK, "Prepare failed");
   /*    * Our test case here involves using a cursor, for which we must be inside    * a transaction block.  We could
dothe whole thing with a single    * PQexec() of "select * from pg_database", but that's too trivial to make    * a
goodexample.    */ 
   /* Start a transaction block */   res = PQexec(conn, "BEGIN");   check_error(conn, res, PGRES_COMMAND_OK, "BEGIN
commandfailed"); 
   /*    * Should PQclear PGresult whenever it is no longer needed to avoid memory    * leaks    */   PQclear(res);
   /*    * Fetch rows from pg_database, the system catalog of databases    */   res = PQexec(conn, "DECLARE myportal
CURSORFOR select * from pg_database");   check_error(conn, res, PGRES_COMMAND_OK, "DECLARE CURSOR failed");
PQclear(res);
   res = PQexec(conn, "FETCH ALL in myportal");   check_error(conn, res, PGRES_TUPLES_OK, "FETCH ALL failed");
   /* first, print out the attribute names */   nFields = PQnfields(res);   for (i = 0; i < nFields; i++)
printf("%-15s",PQfname(res, i));   printf("\n\n"); 
   /* next, print out the rows */   for (i = 0; i < PQntuples(res); i++)   {       for (j = 0; j < nFields; j++)
  printf("%-15s", PQgetvalue(res, i, j));       printf("\n");   } 
   PQclear(res);
   /* close the portal ... we don't bother to check for errors ... */   res = PQexec(conn, "CLOSE myportal");
PQclear(res);
   /* end the transaction */   res = PQexec(conn, "END");   PQclear(res);
   /* close the connection to the database and cleanup */   PQfinish(conn);
   return 0;
}