Reinstate missing network_io/win32/socket_pipe.c file.

git-svn-id: https://svn.apache.org/repos/asf/apr/apr/branches/1.8.x@1924302 13f79535-47bb-0310-9956-ffa450edef68

Author: minfrin

CMakeLists.txt

@@ -216,6 +216,7 @@ SET(APR_SOURCES
   network_io/unix/sockaddr.c
   network_io/unix/socket_util.c
   network_io/win32/sendrecv.c
+  network_io/win32/socket_pipe.c
   network_io/win32/sockets.c
   network_io/win32/sockopt.c
   passwd/apr_getpass.c