strerror_r-posix: work around cygwin 1.7.9

[gnulib.git] / m4 / strerror.m4

diff --git a/m4/strerror.m4 b/m4/strerror.m4
index ab15a91..de4ba96 100644 (file)
--- a/m4/strerror.m4
+++ b/m4/strerror.m4
@@ -1,20 +1,60 @@
-# strerror.m4 serial 1
-dnl Copyright (C) 2002 Free Software Foundation, Inc.
-dnl This file is free software, distributed under the terms of the GNU
-dnl General Public License.  As a special exception to the GNU General
-dnl Public License, this file may be distributed as part of a program
-dnl that contains a configuration script generated by Autoconf, under
-dnl the same distribution terms as the rest of that program.
+# strerror.m4 serial 13
+dnl Copyright (C) 2002, 2007-2011 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.
 
 AC_DEFUN([gl_FUNC_STRERROR],
 [
-  AC_REPLACE_FUNCS(strerror)
-  if test $ac_cv_func_strerror = no; then
-    gl_PREREQ_STRERROR
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_REQUIRE([gl_HEADER_ERRNO_H])
+  m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
+    AC_REQUIRE([gl_FUNC_STRERROR_R_WORKS])
+  ])
+  if test -z "$ERRNO_H"; then
+    AC_CACHE_CHECK([for working strerror function],
+     [gl_cv_func_working_strerror],
+     [AC_RUN_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#include <string.h>
+             #include <errno.h>
+           ]],
+           [[int result = 0;
+             if (!*strerror (-2)) result |= 1;
+             errno = 0;
+             if (!*strerror (0)) result |= 2;
+             if (errno) result |= 4;
+             return result;]])],
+        [gl_cv_func_working_strerror=yes],
+        [gl_cv_func_working_strerror=no],
+        [dnl Be pessimistic on cross-compiles for now.
+         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
+    dnl If the system's strerror_r clobbers strerror, we must replace strerror.
+    case $gl_cv_func_strerror_r_works in
+      *no) REPLACE_STRERROR=1 ;;
+    esac
+  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
 ])
 
 # 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
 ])