issue #1746656: Fix for OS X. configure and #include changes so that the socket
module compiles again on OS X with its more annoying #include requirements.
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 701af2f..d3f65aa 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -256,6 +256,14 @@
 #include <sys/types.h>
 #endif
 
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+
+#ifdef HAVE_NET_IF_H
+#include <net/if.h>
+#endif
+
 /* Generic socket object definitions and includes */
 #define PySocket_BUILDING_SOCKET
 #include "socketmodule.h"