--- orig/libarch/cmd-file-find.c
+++ mod/libarch/cmd-file-find.c
@@ -169,7 +169,11 @@
     invariant (!str_cmp_prefix (tree_root, filedir_path)
                && (!filedir_path[str_length (tree_root)] || ('/' == filedir_path[str_length (tree_root)])));
 
-    filedir_loc = str_alloc_cat (0, "./", filedir_path + str_length (tree_root) + 1);
+    if (!filedir_path[str_length (tree_root)])
+      filedir_loc = str_save (0, "./");
+    else
+      filedir_loc = str_alloc_cat (0, "./", filedir_path + str_length (tree_root) + 1);
+    
     file_tail = file_name_tail (0, filespec);
     mod_loc = file_name_in_vicinity (0, filedir_loc, file_tail);