1 files changed, 56 insertions, 27 deletions

diff --git a/gl/m4/sys_socket_h.m4 b/gl/m4/sys_socket_h.m4
index 94863776..5676a0d2 100644
--- a/gl/m4/sys_socket_h.m4
+++ b/gl/m4/sys_socket_h.m4
@@ -1,12 +1,12 @@
-# sys_socket_h.m4 serial 23
-dnl Copyright (C) 2005-2013 Free Software Foundation, Inc.
+# sys_socket_h.m4 serial 28
+dnl Copyright (C) 2005-2021 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.
 
 dnl From Simon Josefsson.
 
-AC_DEFUN([gl_HEADER_SYS_SOCKET],
+AC_DEFUN_ONCE([gl_SYS_SOCKET_H],
 [
   AC_REQUIRE([gl_SYS_SOCKET_H_DEFAULTS])
   AC_REQUIRE([AC_CANONICAL_HOST])
@@ -95,6 +95,8 @@ AC_DEFUN([gl_HEADER_SYS_SOCKET],
 #include <sys/socket.h>
     ]], [socket connect accept bind getpeername getsockname getsockopt
     listen recv send recvfrom sendto setsockopt shutdown accept4])
+
+  AC_REQUIRE([AC_C_RESTRICT])
 ])
 
 AC_DEFUN([gl_PREREQ_SYS_H_SOCKET],
@@ -104,17 +106,11 @@ AC_DEFUN([gl_PREREQ_SYS_H_SOCKET],
   gl_CHECK_NEXT_HEADERS([sys/socket.h])
   if test $ac_cv_header_sys_socket_h = yes; then
     HAVE_SYS_SOCKET_H=1
-    HAVE_WS2TCPIP_H=0
   else
     HAVE_SYS_SOCKET_H=0
-    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_WS2TCPIP_H])
+  gl_PREREQ_SYS_H_WS2TCPIP
 ])
 
 # Common prerequisites of the <sys/socket.h> replacement and of the
@@ -142,32 +138,65 @@ AC_DEFUN([gl_PREREQ_SYS_H_WINSOCK2],
   AC_SUBST([HAVE_WINSOCK2_H])
 ])
 
+# Common prerequisites of the <sys/socket.h> replacement and of the
+# <arpa/inet.h> replacement.
+# Sets and substitutes HAVE_WS2TCPIP_H.
+AC_DEFUN([gl_PREREQ_SYS_H_WS2TCPIP],
+[
+  AC_REQUIRE([gl_CHECK_SOCKET_HEADERS])
+  if test $ac_cv_header_sys_socket_h = yes; then
+    HAVE_WS2TCPIP_H=0
+  else
+    if test $ac_cv_header_ws2tcpip_h = yes; then
+      HAVE_WS2TCPIP_H=1
+    else
+      HAVE_WS2TCPIP_H=0
+    fi
+  fi
+  AC_SUBST([HAVE_WS2TCPIP_H])
+])
+
+# gl_SYS_SOCKET_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_SYS_SOCKET_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_SYS_SOCKET_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_SYS_SOCKET_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_SYS_SOCKET_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_SYS_SOCKET_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SOCKET])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CONNECT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ACCEPT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_BIND])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETPEERNAME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETSOCKNAME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETSOCKOPT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LISTEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RECV])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SEND])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RECVFROM])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SENDTO])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SETSOCKOPT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SHUTDOWN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ACCEPT4])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_SYS_SOCKET_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_SYS_SOCKET_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_SYS_SOCKET_H_DEFAULTS],
 [
-  GNULIB_SOCKET=0;      AC_SUBST([GNULIB_SOCKET])
-  GNULIB_CONNECT=0;     AC_SUBST([GNULIB_CONNECT])
-  GNULIB_ACCEPT=0;      AC_SUBST([GNULIB_ACCEPT])
-  GNULIB_BIND=0;        AC_SUBST([GNULIB_BIND])
-  GNULIB_GETPEERNAME=0; AC_SUBST([GNULIB_GETPEERNAME])
-  GNULIB_GETSOCKNAME=0; AC_SUBST([GNULIB_GETSOCKNAME])
-  GNULIB_GETSOCKOPT=0;  AC_SUBST([GNULIB_GETSOCKOPT])
-  GNULIB_LISTEN=0;      AC_SUBST([GNULIB_LISTEN])
-  GNULIB_RECV=0;        AC_SUBST([GNULIB_RECV])
-  GNULIB_SEND=0;        AC_SUBST([GNULIB_SEND])
-  GNULIB_RECVFROM=0;    AC_SUBST([GNULIB_RECVFROM])
-  GNULIB_SENDTO=0;      AC_SUBST([GNULIB_SENDTO])
-  GNULIB_SETSOCKOPT=0;  AC_SUBST([GNULIB_SETSOCKOPT])
-  GNULIB_SHUTDOWN=0;    AC_SUBST([GNULIB_SHUTDOWN])
-  GNULIB_ACCEPT4=0;     AC_SUBST([GNULIB_ACCEPT4])
   HAVE_STRUCT_SOCKADDR_STORAGE=1; AC_SUBST([HAVE_STRUCT_SOCKADDR_STORAGE])
   HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY=1;
                         AC_SUBST([HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY])