diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index b5be4baa44..360524f50a 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -30,7 +30,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$PostgreSQL: pgsql/src/backend/libpq/pqcomm.c,v 1.211 2010/07/08 10:20:12 mha Exp $
+ *	$PostgreSQL: pgsql/src/backend/libpq/pqcomm.c,v 1.212 2010/07/08 16:19:50 mha Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -83,7 +83,7 @@
 #ifdef HAVE_UTIME_H
 #include <utime.h>
 #endif
-#ifdef WIN32
+#ifdef WIN32_ONLY_COMPILER /* mstcpip.h is missing on mingw */
 #include <mstcpip.h>
 #endif
 
@@ -1323,7 +1323,7 @@ pq_endcopyout(bool errorAbort)
  * actually set them to zero, not default), therefor we fallback to
  * the out-of-the-box default instead.
  */
-#ifdef WIN32
+#if defined(WIN32) && defined(SIO_KEEPALIVE_VALS)
 static int
 pq_setkeepaliveswin32(Port *port, int idle, int interval)
 {
@@ -1412,7 +1412,7 @@ pq_setkeepalivesidle(int idle, Port *port)
 	if (port == NULL || IS_AF_UNIX(port->laddr.addr.ss_family))
 		return STATUS_OK;
 
-#if defined(TCP_KEEPIDLE) || defined(TCP_KEEPALIVE) || defined(WIN32)
+#if defined(TCP_KEEPIDLE) || defined(TCP_KEEPALIVE) || defined(SIO_KEEPALIVE_VALS)
 	if (idle == port->keepalives_idle)
 		return STATUS_OK;
 
@@ -1451,7 +1451,7 @@ pq_setkeepalivesidle(int idle, Port *port)
 #else /* WIN32 */
 	return pq_setkeepaliveswin32(port, idle, port->keepalives_interval);
 #endif
-#else /* TCP_KEEPIDLE || WIN32 */
+#else /* TCP_KEEPIDLE || SIO_KEEPALIVE_VALS */
 	if (idle != 0)
 	{
 		elog(LOG, "setting the keepalive idle time is not supported");
@@ -1464,7 +1464,7 @@ pq_setkeepalivesidle(int idle, Port *port)
 int
 pq_getkeepalivesinterval(Port *port)
 {
-#if defined(TCP_KEEPINTVL) || defined(WIN32)
+#if defined(TCP_KEEPINTVL) || defined(SIO_KEEPALIVE_VALS)
 	if (port == NULL || IS_AF_UNIX(port->laddr.addr.ss_family))
 		return 0;
 
@@ -1501,7 +1501,7 @@ pq_setkeepalivesinterval(int interval, Port *port)
 	if (port == NULL || IS_AF_UNIX(port->laddr.addr.ss_family))
 		return STATUS_OK;
 
-#if defined(TCP_KEEPINTVL) || defined (WIN32)
+#if defined(TCP_KEEPINTVL) || defined (SIO_KEEPALIVE_VALS)
 	if (interval == port->keepalives_interval)
 		return STATUS_OK;
 
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 5f671f3299..4c59ca6834 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.397 2010/07/08 10:20:12 mha Exp $
+ *	  $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.398 2010/07/08 16:19:50 mha Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -38,7 +38,9 @@
 #endif
 #define near
 #include <shlobj.h>
+#ifdef WIN32_ONLY_COMPILER /* mstcpip.h is missing on mingw */
 #include <mstcpip.h>
+#endif
 #else
 #include <sys/socket.h>
 #include <netdb.h>
@@ -1093,6 +1095,7 @@ setKeepalivesCount(PGconn *conn)
 }
 
 #else /* Win32 */
+#ifdef SIO_KEEPALIVE_VALS
 /*
  * Enable keepalives and set the keepalive values on Win32,
  * where they are always set in one batch.
@@ -1137,6 +1140,7 @@ setKeepalivesWin32(PGconn *conn)
 	}
 	return 1;
 }
+#endif /* SIO_KEEPALIVE_VALS */
 #endif /* WIN32 */
 
 /* ----------
@@ -1555,8 +1559,10 @@ keep_going:						/* We will come back to here until there is
 								 || !setKeepalivesCount(conn))
 							err = 1;
 #else /* WIN32 */
+#ifdef SIO_KEEPALIVE_VALS
 						else if (!setKeepalivesWin32(conn))
 							err = 1;
+#endif /* SIO_KEEPALIVE_VALS */
 #endif /* WIN32 */
 
 						if (err)