PR lto/81004
	* lto.c: Include builtins.h
	(register_resolution): Merge resolutions in case trees was
	merged across units.
	(lto_maybe_register_decl): Break out from ...
	(lto_read_decls): ... here.
	(unify_scc): Also register decls here.
	(read_cgraph_and_symbols): Sanity check that all resolutions was
	read.

From-SVN: r257412