re PR c++/48035 (Mismatch on size of class when initializing hierarchy involving virtual inheritance and empty base classes)

	PR c++/48035
	* init.c (build_zero_init_1): Extracted from build_zero_init.
	Add FIELD_SIZE argument, if non-NULL and field bit_position
	as not smaller than that, don't add that field's initializer.
	Pass DECL_SIZE as last argument to build_zero_init_1
	for DECL_FIELD_IS_BASE fields.
	(build_zero_init): Use build_zero_init_1.

	* g++.dg/inherit/virtual8.C: New test.

From-SVN: r170874