Import upstream version 1.29

[debian/tar] / m4 / symlinkat.m4

diff --git a/m4/symlinkat.m4 b/m4/symlinkat.m4
index db7ad487dd8b3db8c601cf169f2d946dbe312e4f..fd975c89e09461cd2cf49f88b1b4840c3cdcad65 100644 (file)
--- a/m4/symlinkat.m4
+++ b/m4/symlinkat.m4
@@ -1,7 +1,7 @@
-# serial 5
+# serial 6
 # See if we need to provide symlinkat replacement.
 
-dnl Copyright (C) 2009-2014 Free Software Foundation, Inc.
+dnl Copyright (C) 2009-2015 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.
@@ -16,5 +16,38 @@ AC_DEFUN([gl_FUNC_SYMLINKAT],
   AC_CHECK_FUNCS_ONCE([symlinkat])
   if test $ac_cv_func_symlinkat = no; then
     HAVE_SYMLINKAT=0
+  else
+    AC_CACHE_CHECK([whether symlinkat handles trailing slash correctly],
+      [gl_cv_func_symlinkat_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <fcntl.h>
+             #include <unistd.h>
+           ]],
+           [[int result = 0;
+             if (!symlinkat ("a", AT_FDCWD, "conftest.link/"))
+               result |= 1;
+             if (symlinkat ("conftest.f", AT_FDCWD, "conftest.lnk2"))
+               result |= 2;
+             else if (!symlinkat ("a", AT_FDCWD, "conftest.lnk2/"))
+               result |= 4;
+             return result;
+           ]])],
+         [gl_cv_func_symlinkat_works=yes],
+         [gl_cv_func_symlinkat_works=no],
+         [case "$host_os" in
+                    # Guess yes on glibc systems.
+            *-gnu*) gl_cv_func_symlinkat_works="guessing yes" ;;
+                    # If we don't know, assume the worst.
+            *)      gl_cv_func_symlinkat_works="guessing no" ;;
+          esac
+         ])
+      rm -f conftest.f conftest.link conftest.lnk2])
+    case "$gl_cv_func_symlinkat_works" in
+      *yes) ;;
+      *)
+        REPLACE_SYMLINKAT=1
+        ;;
+    esac
   fi
 ])