lto-partition.c: Include sreal.h

	* lto-partition.c: Include sreal.h
	(add_symbol_to_partition_1): Use size instead of self_size
	for size estimate.
	(account_reference_p): New.
	(lto_balanced_map): Use 64bit arithmetics for size calculatoins; cleanup;
	fix accounting errors in boundary size; add debug output; combine cost
	as cost/size instead of cost/internal; reduce the partitioning error to
	+- 1/8 of the parttion size.

From-SVN: r259749