+ [gl_SOCKET_HEADERS])])
+
+dnl On mingw32, socklen_t is in ws2tcpip.h ('int'), so we try to find
+dnl it there too. But on Cygwin, wc2tcpip.h must not be included. Users
+dnl of this module should use the same include pattern as gl_SOCKET_HEADERS.
+dnl When you change this macro, keep also in sync:
+dnl - gl_CHECK_SOCKET_HEADERS,
+dnl - the Include section of modules/socklen.
+AC_DEFUN([gl_SOCKET_HEADERS],
+[
+/* <sys/types.h> is not needed according to POSIX, but the
+ <sys/socket.h> in i386-unknown-freebsd4.10 and
+ powerpc-apple-darwin5.5 required it. */
+#include <sys/types.h>
+#if HAVE_SYS_SOCKET_H
+# include <sys/socket.h>
+#elif HAVE_WS2TCPIP_H
+# include <ws2tcpip.h>
+#endif
+])
+
+dnl Tests for the existence of the header for socket facilities.
+dnl Defines the C macros HAVE_SYS_SOCKET_H, HAVE_WS2TCPIP_H.
+dnl This macro must match gl_SOCKET_HEADERS.
+AC_DEFUN([gl_CHECK_SOCKET_HEADERS],
+ [AC_CHECK_HEADERS_ONCE([sys/socket.h])
+ if test $ac_cv_header_sys_socket_h = no; then
+ 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([ws2tcpip.h])
+ fi
+ ])