Index: src/OFDatagramSocket.m
==================================================================
--- src/OFDatagramSocket.m
+++ src/OFDatagramSocket.m
@@ -12,10 +12,12 @@
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
 #include "config.h"
+
+#define _XOPEN_SOURCE_EXTENDED
 
 #include <errno.h>
 
 #ifdef HAVE_FCNTL_H
 # include <fcntl.h>

Index: src/OFSelectKernelEventObserver.m
==================================================================
--- src/OFSelectKernelEventObserver.m
+++ src/OFSelectKernelEventObserver.m
@@ -11,13 +11,13 @@
  * Public License, either version 2 or 3, which can be found in the file
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
-#define __NO_EXT_QNX
-
 #include "config.h"
+
+#define __NO_EXT_QNX
 
 #include "platform.h"
 
 #ifdef OF_WINDOWS
 /* Win32 has a ridiculous default of 64, even though it supports much more. */
@@ -39,10 +39,15 @@
 #import "socket_helpers.h"
 
 #ifdef OF_AMIGAOS
 # include <proto/exec.h>
 #endif
+
+#ifdef OF_HPUX
+/* FD_SET causes warnings on HP-UX/IA64. */
+# pragma GCC diagnostic ignored "-Wstrict-aliasing"
+#endif
 
 @implementation OFSelectKernelEventObserver
 - (instancetype)init
 {
 	self = [super init];

Index: src/OFSequencedPacketSocket.m
==================================================================
--- src/OFSequencedPacketSocket.m
+++ src/OFSequencedPacketSocket.m
@@ -12,10 +12,12 @@
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
 #include "config.h"
+
+#define _XOPEN_SOURCE_EXTENDED
 
 #include <assert.h>
 #include <errno.h>
 
 #ifdef HAVE_FCNTL_H

Index: src/OFStreamSocket.m
==================================================================
--- src/OFStreamSocket.m
+++ src/OFStreamSocket.m
@@ -11,13 +11,14 @@
  * Public License, either version 2 or 3, which can be found in the file
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
-#define __NO_EXT_QNX
-
 #include "config.h"
+
+#define _XOPEN_SOURCE_EXTENDED
+#define __NO_EXT_QNX
 
 #include <assert.h>
 #include <errno.h>
 #include <string.h>
 

Index: src/OFTCPSocket.m
==================================================================
--- src/OFTCPSocket.m
+++ src/OFTCPSocket.m
@@ -11,13 +11,14 @@
  * Public License, either version 2 or 3, which can be found in the file
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
-#define __NO_EXT_QNX
-
 #include "config.h"
+
+#define _XOPEN_SOURCE_EXTENDED
+#define __NO_EXT_QNX
 
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

Index: src/socket.m
==================================================================
--- src/socket.m
+++ src/socket.m
@@ -12,10 +12,12 @@
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
 #include "config.h"
+
+#define _XOPEN_SOURCE_EXTENDED
 
 #ifdef OF_NINTENDO_3DS
 # include <malloc.h>  /* For memalign() */
 #endif