From 5be04ec2ceb1df77afbca4fcbf9e92a712612d6f Mon Sep 17 00:00:00 2001
From: Lorenz Kästle <12514511+RincewindsHat@users.noreply.github.com>
Date: Thu, 31 Oct 2024 16:27:12 +0100
Subject: Sync with the latest Gnulib code (d4ec02b3cc)

---
 gl/m4/lseek.m4 | 45 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 34 insertions(+), 11 deletions(-)

(limited to 'gl/m4/lseek.m4')

diff --git a/gl/m4/lseek.m4 b/gl/m4/lseek.m4
index fd4f1f27..0bc3d65e 100644
--- a/gl/m4/lseek.m4
+++ b/gl/m4/lseek.m4
@@ -1,5 +1,6 @@
-# lseek.m4 serial 12
-dnl Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
+# lseek.m4
+# serial 15
+dnl Copyright (C) 2007, 2009-2024 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.
@@ -13,13 +14,15 @@ AC_DEFUN([gl_FUNC_LSEEK],
   AC_CHECK_HEADERS_ONCE([unistd.h])
   AC_CACHE_CHECK([whether lseek detects pipes], [gl_cv_func_lseek_pipe],
     [case "$host_os" in
-       mingw*)
+       mingw* | windows*)
          dnl Native Windows.
          dnl The result of lseek (fd, (off_t)0, SEEK_CUR) or
          dnl SetFilePointer(handle, 0, NULL, FILE_CURRENT)
-         dnl for a pipe depends on the environment: In a Cygwin 1.5
-         dnl environment it succeeds (wrong); in a Cygwin 1.7 environment
-         dnl it fails with a wrong errno value.
+         dnl for a pipe depends on the environment:
+         dnl In a Cygwin 1.5 environment it succeeds (wrong);
+         dnl in a Cygwin 1.7 environment it fails with a wrong errno value;
+         dnl in a Cygwin 2.9.0 environment it fails correctly;
+         dnl in a Cygwin 3.4.6 environment it succeeds again (wrong).
          gl_cv_func_lseek_pipe=no
          ;;
        *)
@@ -70,9 +73,29 @@ AC_DEFUN([gl_FUNC_LSEEK],
     REPLACE_LSEEK=1
   fi
 
-  dnl macOS SEEK_DATA is incompatible with other platforms.
-  case $host_os in
-    darwin*)
-      REPLACE_LSEEK=1;;
-  esac
+  AS_IF([test $REPLACE_LSEEK = 0],
+    [AC_CACHE_CHECK([whether SEEK_DATA works but is incompatible with GNU],
+       [gl_cv_func_lseek_works_but_incompatible],
+       [AC_PREPROC_IFELSE(
+          [AC_LANG_SOURCE(
+             dnl Use macOS "9999" to stand for a future fixed macOS version.
+             dnl See ../lib/unistd.in.h and <https://bugs.gnu.org/61386>.
+             [[#include <unistd.h>
+               #if defined __APPLE__ && defined __MACH__ && defined SEEK_DATA
+               # ifdef __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__
+               #  include <AvailabilityMacros.h>
+               # endif
+               # if 99990000 <= MAC_OS_X_VERSION_MIN_REQUIRED
+               #  define LSEEK_WORKS_BUT_IS_INCOMPATIBLE_WITH_GNU
+               # endif
+               #endif
+               #ifndef LSEEK_WORKS_BUT_IS_INCOMPATIBLE_WITH_GNU
+                #error "No need to work around the bug"
+               #endif
+             ]])],
+          [gl_cv_func_lseek_works_but_incompatible=yes],
+          [gl_cv_func_lseek_works_but_incompatible=no])])
+     if test "$gl_cv_func_lseek_works_but_incompatible" = yes; then
+       REPLACE_LSEEK=1
+     fi])
 ])
-- 
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