[libxml2] autotools: Fix network checks on Windows

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 9e5a016ef039db536d30d016e5b9226c70b3c66a
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Mon Sep 5 01:08:33 2022 +0200

    autotools: Fix network checks on Windows

 configure.ac          | 12 ++++++++++--
 include/wsockcompat.h |  3 ++-
 2 files changed, 12 insertions(+), 3 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 82638d6a..eb03a83c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -370,7 +370,11 @@ dnl Determine what socket length (socklen_t) data type is
 AC_MSG_CHECKING([for type of socket length (socklen_t)])
 AC_TRY_COMPILE2([
 #include <stddef.h>
-#include <sys/socket.h>],[
+#ifdef _WIN32
+  #include <ws2tcpip.h>
+#else
+  #include <sys/socket.h>
+#endif],[
 (void)getsockopt (1, 1, 1, NULL, (socklen_t *)NULL)],[
   AC_MSG_RESULT(socklen_t *)
   XML_SOCKLEN_T=socklen_t],[
@@ -402,7 +406,11 @@ fi
 if test $enable_ipv6 = yes; then
   have_ipv6=no
   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-#   include <sys/socket.h>
+    #ifdef _WIN32
+      #include <winsock2.h>
+    #else
+      #include <sys/socket.h>
+    #endif
     ]], [[
     struct sockaddr_storage ss;
     socket(AF_INET6, SOCK_STREAM, 0)
diff --git a/include/wsockcompat.h b/include/wsockcompat.h
index 85b9e7d5..b3c97165 100644
--- a/include/wsockcompat.h
+++ b/include/wsockcompat.h
@@ -28,8 +28,9 @@
 #define HAVE_GETADDRINFO
 #endif
 
-#undef XML_SOCKLEN_T
+#ifndef XML_SOCKLEN_T
 #define XML_SOCKLEN_T int
+#endif
 
 #ifndef ECONNRESET
 #define ECONNRESET WSAECONNRESET