+/* fileAction return value of 0 on any file in directory will make
+ * recursive_action() return 0, but it doesn't stop directory traversal
+ * (fileAction/dirAction will be called on each file).
+ *
+ * If !ACTION_RECURSE, dirAction is called on the directory and its
+ * return value is returned from recursive_action(). No recursion.
+ *
+ * If ACTION_RECURSE, recursive_action() is called on each directory.
+ * If any one of these calls returns 0, current recursive_action() returns 0.
+ *
+ * If ACTION_DEPTHFIRST, dirAction is called after recurse.
+ * If it returns 0, the warning is printed and recursive_action() returns 0.
+ *
+ * If !ACTION_DEPTHFIRST, dirAction is called before we recurse.
+ * Return value of 0 (FALSE) or 2 (SKIP) prevents recursion
+ * into that directory, instead recursive_action() returns 0 (if FALSE)
+ * or 1 (if SKIP)
+ *
+ * ACTION_FOLLOWLINKS mainly controls handling of links to dirs.