follow symlinks when browsing the directory tree

Sometime we are interested in following the symlinks, sometime not.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
diff --git a/tree.h b/tree.h
index c7f3ca9..5c1c697 100644
--- a/tree.h
+++ b/tree.h
@@ -41,7 +41,7 @@
 
 typedef int (*tree_filter_t)(const char *name);
 
-extern struct tree *tree_load(const char *path, tree_filter_t filter);
+extern struct tree *tree_load(const char *path, tree_filter_t filter, bool follow);
 
 extern struct tree *tree_find(struct tree *tree, const char *name);