1 files changed, 72 insertions, 44 deletions

diff --git a/gl/m4/strerror.m4 b/gl/m4/strerror.m4
index 1649b245..3989844b 100644
--- a/gl/m4/strerror.m4
+++ b/gl/m4/strerror.m4
@@ -1,68 +1,96 @@
-# strerror.m4 serial 9
-dnl Copyright (C) 2002, 2007-2010 Free Software Foundation, Inc.
+# strerror.m4 serial 17
+dnl Copyright (C) 2002, 2007-2013 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_REQUIRE([gl_FUNC_STRERROR_SEPARATE])
-  if test $REPLACE_STRERROR = 1; then
-    AC_LIBOBJ([strerror])
-    AC_DEFINE_UNQUOTED([REPLACE_STRERROR], [$REPLACE_STRERROR],
-      [Define this to 1 if strerror is broken.])
-  fi
-])
-
-# Like gl_FUNC_STRERROR, except prepare for separate compilation (no AC_LIBOBJ).
-AC_DEFUN([gl_FUNC_STRERROR_SEPARATE],
-[
   AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
   AC_REQUIRE([gl_HEADER_ERRNO_H])
-  if test -z "$ERRNO_H"; then
+  AC_REQUIRE([gl_FUNC_STRERROR_0])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
+    AC_REQUIRE([gl_FUNC_STRERROR_R_WORKS])
+  ])
+  if test "$ERRNO_H:$REPLACE_STRERROR_0" = :0; then
     AC_CACHE_CHECK([for working strerror function],
      [gl_cv_func_working_strerror],
      [AC_RUN_IFELSE(
         [AC_LANG_PROGRAM(
            [[#include <string.h>
            ]],
-           [[return !*strerror (-2);]])],
+           [[if (!*strerror (-2)) return 1;]])],
         [gl_cv_func_working_strerror=yes],
         [gl_cv_func_working_strerror=no],
-        [dnl Assume crossbuild works if it compiles.
-         AC_COMPILE_IFELSE(
-           [AC_LANG_PROGRAM(
-              [[#include <string.h>
-              ]],
-              [[return !*strerror (-2);]])],
-           [gl_cv_func_working_strerror=yes],
-           [gl_cv_func_working_strerror=no])
-      ])
+        [case "$host_os" in
+                   # Guess yes on glibc systems.
+           *-gnu*) gl_cv_func_working_strerror="guessing yes" ;;
+                   # If we don't know, assume the worst.
+           *)      gl_cv_func_working_strerror="guessing no" ;;
+         esac
+        ])
+    ])
+    case "$gl_cv_func_working_strerror" in
+      *yes) ;;
+      *)
+        dnl The system's strerror() fails to return a string for out-of-range
+        dnl integers. Replace it.
+        REPLACE_STRERROR=1
+        ;;
+    esac
+    m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
+      dnl If the system's strerror_r or __xpg_strerror_r clobbers strerror's
+      dnl buffer, we must replace strerror.
+      case "$gl_cv_func_strerror_r_works" in
+        *no) REPLACE_STRERROR=1 ;;
+      esac
     ])
-    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.
+    dnl to <errno.h>, or any fix for strerror(0). Replace it.
     REPLACE_STRERROR=1
   fi
-  if test $REPLACE_STRERROR = 1; then
-    gl_PREREQ_STRERROR
-  fi
 ])
 
-# Prerequisites of lib/strerror.c.
-AC_DEFUN([gl_PREREQ_STRERROR], [
-  AC_CHECK_DECLS([strerror])
-  AC_CHECK_HEADERS_ONCE([sys/socket.h])
-  if test $ac_cv_header_sys_socket_h != yes; then
-    dnl We cannot use AC_CHECK_HEADERS_ONCE here, because that would make
-    dnl the check for those headers unconditional; yet cygwin reports
-    dnl that the headers are present but cannot be compiled (since on
-    dnl cygwin, all socket information should come from sys/socket.h).
-    AC_CHECK_HEADERS([winsock2.h])
-  fi
+dnl Detect if strerror(0) passes (that is, does not set errno, and does not
+dnl return a string that matches strerror(-1)).
+AC_DEFUN([gl_FUNC_STRERROR_0],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  REPLACE_STRERROR_0=0
+  AC_CACHE_CHECK([whether strerror(0) succeeds],
+   [gl_cv_func_strerror_0_works],
+   [AC_RUN_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[#include <string.h>
+           #include <errno.h>
+         ]],
+         [[int result = 0;
+           char *str;
+           errno = 0;
+           str = strerror (0);
+           if (!*str) result |= 1;
+           if (errno) result |= 2;
+           if (strstr (str, "nknown") || strstr (str, "ndefined"))
+             result |= 4;
+           return result;]])],
+      [gl_cv_func_strerror_0_works=yes],
+      [gl_cv_func_strerror_0_works=no],
+      [case "$host_os" in
+                 # Guess yes on glibc systems.
+         *-gnu*) gl_cv_func_strerror_0_works="guessing yes" ;;
+                 # If we don't know, assume the worst.
+         *)      gl_cv_func_strerror_0_works="guessing no" ;;
+       esac
+      ])
+  ])
+  case "$gl_cv_func_strerror_0_works" in
+    *yes) ;;
+    *)
+      REPLACE_STRERROR_0=1
+      AC_DEFINE([REPLACE_STRERROR_0], [1], [Define to 1 if strerror(0)
+        does not return a message implying success.])
+      ;;
+  esac
 ])