document mingw linker fix and close associated bug

[debian/gzip] / m4 / utimens.m4

diff --git a/m4/utimens.m4 b/m4/utimens.m4
index 97a99ea25c2b8de2135f3ebf7f633742616b95e6..9a4db07a3dae4a3526c66f881eaed675f0f1acf2 100644 (file)
--- a/m4/utimens.m4
+++ b/m4/utimens.m4
@@ -1,16 +1,51 @@
-dnl Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+dnl Copyright (C) 2003-2018 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 serial 9
+
 AC_DEFUN([gl_UTIMENS],
 [
-  AC_LIBOBJ([utimens])
-
   dnl Prerequisites of lib/utimens.c.
-  AC_REQUIRE([gl_TIMESPEC])
   AC_REQUIRE([gl_FUNC_UTIMES])
   AC_REQUIRE([gl_CHECK_TYPE_STRUCT_TIMESPEC])
-  AC_REQUIRE([gl_CHECK_TYPE_STRUCT_UTIMBUF])
-  AC_CHECK_FUNCS_ONCE([futimes futimesat])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_FUNCS_ONCE([futimes futimesat futimens utimensat lutimes])
+
+  if test $ac_cv_func_futimens = no && test $ac_cv_func_futimesat = yes; then
+    dnl FreeBSD 8.0-rc2 mishandles futimesat(fd,NULL,time).  It is not
+    dnl standardized, but Solaris implemented it first and uses it as
+    dnl its only means to set fd time.
+    AC_CACHE_CHECK([whether futimesat handles NULL file],
+      [gl_cv_func_futimesat_works],
+      [touch conftest.file
+       AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <stddef.h>
+#include <sys/times.h>
+#include <fcntl.h>
+]], [[    int fd = open ("conftest.file", O_RDWR);
+          if (fd < 0) return 1;
+          if (futimesat (fd, NULL, NULL)) return 2;
+        ]])],
+        [gl_cv_func_futimesat_works=yes],
+        [gl_cv_func_futimesat_works=no],
+        [case "$host_os" in
+                            # Guess yes on Linux systems.
+           linux-* | linux) gl_cv_func_futimesat_works="guessing yes" ;;
+                            # Guess yes on glibc systems.
+           *-gnu*)          gl_cv_func_futimesat_works="guessing yes" ;;
+                            # If we don't know, assume the worst.
+           *)               gl_cv_func_futimesat_works="guessing no" ;;
+         esac
+        ])
+      rm -f conftest.file])
+    case "$gl_cv_func_futimesat_works" in
+      *yes) ;;
+      *)
+        AC_DEFINE([FUTIMESAT_NULL_BUG], [1],
+          [Define to 1 if futimesat mishandles a NULL file name.])
+        ;;
+    esac
+  fi
 ])