Fix building the BFD library for Win64 by reqorking the find_separate_debug_file...

Fix building the BFD library for Win64 by reqorking the find_separate_debug_file interface.

	* opncls.c (bfd_get_debug_link_info): Rename to...
	(bfd_get_debug_link_info_1): ... this.  Change type of second
	parameter to void pointer.  Adjust.
	(bfd_get_debug_link_info): Reimplement on top of
	bfd_get_debug_link_info_1.
	(separate_debug_file_exists, separate_alt_debug_file_exists):
	Change type of second parameter to void pointer.  Adjust.
	(get_func_type, check_func_type): Change type of second parameter
	to void pointer.
	(find_separate_debug_file): Add 'func_data' parameter.  Pass it to
	the callback functions instead of passing the address of a local.
	(bfd_follow_gnu_debuglink): Pass address of unsigned long local to
	find_separate_debug_file.
	(get_alt_debug_link_info_shim): Change type of second parameter to
	void pointer.  Adjust.
	(bfd_follow_gnu_debugaltlink): Adjust to pass NULL to
	find_separate_debug_file.
	(get_build_id_name, bfd_boolean check_build_id_file): Change type
	of second parameter to void pointer.  Adjust.
	(bfd_follow_build_id_debuglink): Pass address of bfd_build_id
	pointer local to find_separate_debug_file.