1 files changed, 42 insertions, 21 deletions

diff --git a/gl/m4/strerror.m4 b/gl/m4/strerror.m4
index eb7d45aa..8c16ca9a 100644
--- a/gl/m4/strerror.m4
+++ b/gl/m4/strerror.m4
@@ -1,5 +1,5 @@
-# strerror.m4 serial 7
-dnl Copyright (C) 2002, 2007 Free Software Foundation, Inc.
+# strerror.m4 serial 9
+dnl Copyright (C) 2002, 2007-2008 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.
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_STRERROR],
 [
   AC_REQUIRE([gl_FUNC_STRERROR_SEPARATE])
-  if test $gl_cv_func_working_strerror = no; then
+  if test $REPLACE_STRERROR = 1; then
     AC_LIBOBJ([strerror])
     AC_DEFINE_UNQUOTED([REPLACE_STRERROR], [$REPLACE_STRERROR],
       [Define this to 1 if strerror is broken.])
@@ -18,25 +18,38 @@ AC_DEFUN([gl_FUNC_STRERROR],
 AC_DEFUN([gl_FUNC_STRERROR_SEPARATE],
 [
   AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
-  AC_CACHE_CHECK([for working strerror function],
-   [gl_cv_func_working_strerror],
-   [AC_RUN_IFELSE(
-      [AC_LANG_PROGRAM(
-         [#include <string.h>
-         ],
-         [return !*strerror (-2);])],
-      [gl_cv_func_working_strerror=yes],
-      [gl_cv_func_working_strerror=no],
-      [dnl Assume crossbuild works if it compiles.
-       AC_COMPILE_IFELSE(
-         [AC_LANG_PROGRAM(
-            [#include <string.h>
-            ],
-            [return !*strerror (-2);])],
-         [gl_cv_func_working_strerror=yes],
-         [gl_cv_func_working_strerror=no])])])
-  if test $gl_cv_func_working_strerror = no ; then
+  AC_REQUIRE([gl_HEADER_ERRNO_H])
+  if test -z "$ERRNO_H"; then
+    AC_CACHE_CHECK([for working strerror function],
+     [gl_cv_func_working_strerror],
+     [AC_RUN_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#include <string.h>
+           ]],
+           [[return !*strerror (-2);]])],
+        [gl_cv_func_working_strerror=yes],
+        [gl_cv_func_working_strerror=no],
+        [dnl Assume crossbuild works if it compiles.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[#include <string.h>
+              ]],
+              [[return !*strerror (-2);]])],
+           [gl_cv_func_working_strerror=yes],
+           [gl_cv_func_working_strerror=no])
+      ])
+    ])
+    if test $gl_cv_func_working_strerror = no; then
+      dnl The system's strerror() fails to return a string for out-of-range
+      dnl integers. Replace it.
+      REPLACE_STRERROR=1
+    fi
+  else
+    dnl The system's strerror() cannot know about the new errno values we add
+    dnl to <errno.h>. Replace it.
     REPLACE_STRERROR=1
+  fi
+  if test $REPLACE_STRERROR = 1; then
     gl_PREREQ_STRERROR
   fi
 ])
@@ -44,4 +57,12 @@ AC_DEFUN([gl_FUNC_STRERROR_SEPARATE],
 # Prerequisites of lib/strerror.c.
 AC_DEFUN([gl_PREREQ_STRERROR], [
   AC_CHECK_DECLS([strerror])
+  AC_CHECK_HEADERS_ONCE([sys/socket.h])
+  if test $ac_cv_header_sys_socket_h != yes; 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([winsock2.h])
+  fi
 ])