X-Git-Url: https://git.cworth.org/git?p=tar;a=blobdiff_plain;f=m4%2Flstat.m4;fp=m4%2Flstat.m4;h=236af540e0321a95a4b83af0df5891565cebb7de;hp=5dbd16e28ffe875a46d4696df5a4a164b32b929f;hb=ee168310ec4227174ace489bf5f81f8c2f91cde0;hpb=22f1eb8bc17e5be72dd23d42d6aaa60196ac22e6

diff --git a/m4/lstat.m4 b/m4/lstat.m4
index 5dbd16e..236af54 100644
--- a/m4/lstat.m4
+++ b/m4/lstat.m4
@@ -1,4 +1,4 @@
-# serial 20
+# serial 21
 
 # Copyright (C) 1997-2001, 2003-2010 Free Software Foundation, Inc.
 #
@@ -26,3 +26,44 @@ AC_DEFUN([gl_FUNC_LSTAT],
     HAVE_LSTAT=0
   fi
 ])
+
+# Redefine AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, because it is no longer
+# maintained in Autoconf.
+AC_DEFUN([AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK],
+[
+  AC_CACHE_CHECK([whether lstat correctly handles trailing slash],
+    [ac_cv_func_lstat_dereferences_slashed_symlink],
+    [rm -f conftest.sym conftest.file
+     echo >conftest.file
+     if test "$as_ln_s" = "ln -s" && ln -s conftest.file conftest.sym; then
+       AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [AC_INCLUDES_DEFAULT],
+            [[struct stat sbuf;
+              /* Linux will dereference the symlink and fail, as required by
+                 POSIX.  That is better in the sense that it means we will not
+                 have to compile and use the lstat wrapper.  */
+              return lstat ("conftest.sym/", &sbuf) == 0;
+            ]])],
+         [ac_cv_func_lstat_dereferences_slashed_symlink=yes],
+         [ac_cv_func_lstat_dereferences_slashed_symlink=no],
+         [# When cross-compiling, be pessimistic so we will end up using the
+          # replacement version of lstat that checks for trailing slashes and
+          # calls lstat a second time when necessary.
+          ac_cv_func_lstat_dereferences_slashed_symlink=no
+         ])
+     else
+       # If the 'ln -s' command failed, then we probably don't even
+       # have an lstat function.
+       ac_cv_func_lstat_dereferences_slashed_symlink=no
+     fi
+     rm -f conftest.sym conftest.file
+    ])
+  test $ac_cv_func_lstat_dereferences_slashed_symlink = yes &&
+    AC_DEFINE_UNQUOTED([LSTAT_FOLLOWS_SLASHED_SYMLINK], [1],
+      [Define to 1 if `lstat' dereferences a symlink specified
+       with a trailing slash.])
+  if test "x$ac_cv_func_lstat_dereferences_slashed_symlink" = xno; then
+    AC_LIBOBJ([lstat])
+  fi
+])