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/configure.in b/configure.in
index 3ae9a34..3bf46b0 100644
--- a/configure.in
+++ b/configure.in
@@ -1293,11 +1293,28 @@
sys/param.h sys/poll.h sys/select.h sys/sendfile.h sys/socket.h sys/statvfs.h \
sys/stat.h sys/termio.h sys/time.h \
sys/times.h sys/types.h sys/uio.h sys/un.h sys/utsname.h sys/wait.h pty.h \
-libutil.h sys/resource.h net/if.h netpacket/packet.h sysexits.h bluetooth.h \
+libutil.h sys/resource.h netpacket/packet.h sysexits.h bluetooth.h \
bluetooth/bluetooth.h linux/tipc.h spawn.h util.h)
AC_HEADER_DIRENT
AC_HEADER_MAJOR
+# On Darwin (OS X) net/if.h requires sys/socket.h to be imported first.
+AC_CHECK_HEADERS([net/if.h], [], [],
+[#include <stdio.h>
+#ifdef STDC_HEADERS
+# include <stdlib.h>
+# include <stddef.h>
+#else
+# ifdef HAVE_STDLIB_H
+# include <stdlib.h>
+# endif
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+# include <sys/socket.h>
+#endif
+])
+
+
# On Solaris, term.h requires curses.h
AC_CHECK_HEADERS(term.h,,,[
#ifdef HAVE_CURSES_H