Force usage of gtar

Index: scripts/miscellaneous/private/tar_is_bsd.m
--- scripts/miscellaneous/private/tar_is_bsd.m.orig
+++ scripts/miscellaneous/private/tar_is_bsd.m
@@ -37,15 +37,6 @@
 
 function out = tar_is_bsd ()
 
-  ## BSD tar needs to be handled differently from GNU tar
-  persistent cache
-  if (isempty (cache))
-    [status, tar_ver_str] = system ("tar --version");
-    if (status)
-      error ("tar: Failed executing tar --version (status = %d)", status);
-    endif
-    cache = ! isempty (regexp (tar_ver_str, "bsdtar"));
-  endif
-  out = cache;
+ out = 0;
 
 endfunction
