Fix the MS-Windows build.

 src/sysdep.c [WINDOWSNT]: Include sys/socket.h, without which this
 file doesn't compile on MS-Windows.

src/ChangeLog

+2014-12-29  Eli Zaretskii  <eliz@gnu.org>
+
+	* sysdep.c [WINDOWSNT]: Include sys/socket.h, without which this
+	file doesn't compile on MS-Windows.
+
 2014-12-28  Paul Eggert  <eggert@cs.ucla.edu>
 	Fix produce_composite_width typo

src/sysdep.c

@@ -110,6 +110,9 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #define _P_WAIT 0
 int _cdecl _spawnlp (int, const char *, const char *, ...);
 int _cdecl _getpid (void);
+/* The following is needed for O_CLOEXEC, F_SETFD, FD_CLOEXEC, and
+   several prototypes of functions called below.  */
+#include <sys/socket.h>
 #endif
 
 #include "syssignal.h"