* dumpfile.c (FIRST_ME_AUTO_NUMBERED_DUMP): Bump to 4.
	* lto-lang.c (lto_link_dump_id, decl_merge_dump_id, partition_dump_id):
	New global vars.
	(lto_register_dumps): New hook.
	(LANG_HOOKS_REGISTER_DUMPS): New.
	* lto-partition.c: Dump into dump_file instead of symtab->dump_file.
	* lto-symtab.c: Include lto.h; dump into dump_file instead of
	symtab->dump_file.
	(lto_symtab_merge_decls): Initialize dump file.
	* lto.c (read_cgraph_and_symbols): Initialize dump file.
	(do_whole_program_analysis): Likewise.

From-SVN: r261337