Index: src/OFDatagramSocket.m
==================================================================
--- src/OFDatagramSocket.m
+++ src/OFDatagramSocket.m
@@ -16,10 +16,11 @@
 #include "config.h"
 
 #ifndef _XOPEN_SOURCE_EXTENDED
 # define _XOPEN_SOURCE_EXTENDED
 #endif
+#define _HPUX_ALT_XOPEN_SOCKET_API
 
 #include <errno.h>
 
 #ifdef HAVE_FCNTL_H
 # include <fcntl.h>

Index: src/OFSequencedPacketSocket.m
==================================================================
--- src/OFSequencedPacketSocket.m
+++ src/OFSequencedPacketSocket.m
@@ -16,10 +16,11 @@
 #include "config.h"
 
 #ifndef _XOPEN_SOURCE_EXTENDED
 # define _XOPEN_SOURCE_EXTENDED
 #endif
+#define _HPUX_ALT_XOPEN_SOCKET_API
 
 #include <assert.h>
 #include <errno.h>
 
 #ifdef HAVE_FCNTL_H

Index: src/OFStreamSocket.m
==================================================================
--- src/OFStreamSocket.m
+++ src/OFStreamSocket.m
@@ -17,10 +17,11 @@
 
 #ifndef _XOPEN_SOURCE_EXTENDED
 # define _XOPEN_SOURCE_EXTENDED
 #endif
 #define __NO_EXT_QNX
+#define _HPUX_ALT_XOPEN_SOCKET_API
 
 #include <assert.h>
 #include <errno.h>
 #include <string.h>
 

Index: src/OFTCPSocket.m
==================================================================
--- src/OFTCPSocket.m
+++ src/OFTCPSocket.m
@@ -17,10 +17,11 @@
 
 #ifndef _XOPEN_SOURCE_EXTENDED
 # define _XOPEN_SOURCE_EXTENDED
 #endif
 #define __NO_EXT_QNX
+#define _HPUX_ALT_XOPEN_SOCKET_API
 
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

Index: src/OFUDPSocket.m
==================================================================
--- src/OFUDPSocket.m
+++ src/OFUDPSocket.m
@@ -13,10 +13,15 @@
  * file.
  */
 
 #include "config.h"
 
+#ifndef _XOPEN_SOURCE_EXTENDED
+# define _XOPEN_SOURCE_EXTENDED
+#endif
+#define _HPUX_ALT_XOPEN_SOCKET_API
+
 #include <errno.h>
 
 #ifdef HAVE_FCNTL_H
 # include <fcntl.h>
 #endif

Index: src/socket.m
==================================================================
--- src/socket.m
+++ src/socket.m
@@ -16,10 +16,11 @@
 #include "config.h"
 
 #ifndef _XOPEN_SOURCE_EXTENDED
 # define _XOPEN_SOURCE_EXTENDED
 #endif
+#define _HPUX_ALT_XOPEN_SOCKET_API
 
 #ifdef OF_NINTENDO_3DS
 # include <malloc.h>  /* For memalign() */
 #endif