1 files changed, 38 insertions, 10 deletions

diff --git a/gl/m4/sys_socket_h.m4 b/gl/m4/sys_socket_h.m4
index d3e45b4..d9659c2 100644
--- a/gl/m4/sys_socket_h.m4
+++ b/gl/m4/sys_socket_h.m4
@@ -1,5 +1,5 @@
-# sys_socket_h.m4 serial 2
-dnl Copyright (C) 2005, 2006 Free Software Foundation, Inc.
+# sys_socket_h.m4 serial 4
+dnl Copyright (C) 2005, 2006, 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -8,16 +8,44 @@ dnl From Simon Josefsson.
 
 AC_DEFUN([gl_HEADER_SYS_SOCKET],
 [
-  AC_CHECK_HEADERS_ONCE([sys/socket.h])
-  if test $ac_cv_header_sys_socket_h = yes; then
+  AC_CACHE_CHECK([whether <sys/socket.h> is self-contained],
+    [gl_cv_header_sys_socket_h_selfcontained],
+    [
+      AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <sys/socket.h>], [])],
+        [gl_cv_header_sys_socket_h_selfcontained=yes],
+        [gl_cv_header_sys_socket_h_selfcontained=no])
+    ])
+  if test $gl_cv_header_sys_socket_h_selfcontained = yes; then
     SYS_SOCKET_H=''
   else
-    dnl We cannot use AC_CHECK_HEADERS_ONCE here, because that would make
-    dnl the check for those headers unconditional; yet cygwin reports
-    dnl that the headers are present but cannot be compiled (since on
-    dnl cygwin, all socket information should come from sys/socket.h).
-    AC_CHECK_HEADERS([winsock2.h ws2tcpip.h])
     SYS_SOCKET_H='sys/socket.h'
+
+    gl_CHECK_NEXT_HEADERS([sys/socket.h])
+    if test $ac_cv_header_sys_socket_h = yes; then
+      HAVE_SYS_SOCKET_H=1
+      HAVE_WINSOCK2_H=0
+      HAVE_WS2TCPIP_H=0
+    else
+      HAVE_SYS_SOCKET_H=0
+      dnl We cannot use AC_CHECK_HEADERS_ONCE here, because that would make
+      dnl the check for those headers unconditional; yet cygwin reports
+      dnl that the headers are present but cannot be compiled (since on
+      dnl cygwin, all socket information should come from sys/socket.h).
+      AC_CHECK_HEADERS([winsock2.h ws2tcpip.h])
+      if test $ac_cv_header_winsock2_h = yes; then
+        HAVE_WINSOCK2_H=1
+      else
+        HAVE_WINSOCK2_H=0
+      fi
+      if test $ac_cv_header_ws2tcpip_h = yes; then
+        HAVE_WS2TCPIP_H=1
+      else
+        HAVE_WS2TCPIP_H=0
+      fi
+    fi
+    AC_SUBST([HAVE_SYS_SOCKET_H])
+    AC_SUBST([HAVE_WINSOCK2_H])
+    AC_SUBST([HAVE_WS2TCPIP_H])
   fi
-  AC_SUBST(SYS_SOCKET_H)
+  AC_SUBST([SYS_SOCKET_H])
 ])