* info.el (Info-file-supports-index-cookies-list): New variable.

* info.el (Info-file-supports-index-cookies-list): New variable.
(Info-file-supports-index-cookies): New function.
(Info-find-node-2, Info-index-nodes, Info-index-node): Use it.
(Info-index-nodes): Let-bind Info-point-loc to nil for files
without an index cookie to ignore it when Info-index-nodes is
called during navigating from an index node with line numbers.
(Info-index-node): Set file to Info-current-file if nil.  (Bug#1118)

* info.el (Info-breadcrumbs-depth): Move defcustom higher to the
variable definition section.