* lib/shadowmem.c: Only copy the required fields of the struct

	* lib/shadowmem.c: Only copy the required fields of the struct
	spwd. (start with the primitive types)
	* lib/shadowmem.c: Avoid memzero() on a possibly NULL pointer.
	* lib/groupmem.c: Only copy the required fields of the struct
	group. (start with the primitive types)
	* lib/groupmem.c: Avoid memzero() on a possibly NULL pointer.
	* lib/groupmem.c: Free gr_mem in addition to its elements.
	* lib/sgroupio.c: The struct sgrp has no primitive types to be
	copied initially.
	* lib/sgroupio.c: Avoid memzero() on a possibly NULL pointer.
	* lib/sgroupio.c: Free sg_mem and sg_add in addition to their
	elements.
	* lib/pwmem.c: Only copy the required fields of the struct
	passwd. (start with the primitive types)