Use XSTAT_IS_XSTAT64 in generic xstat functions

	* sysdeps/unix/sysv/linux/generic/wordsize-32/fxstat.c: Do not define
	fxstat if XSTAT_IS_XSTAT64 is set to non-zero.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/fxstatat.c: Ditto for
	fxstatat.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/lxstat.c: Ditto for
	lxstat.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/xstat.c: Ditto for xstat.

	* sysdeps/unix/sysv/linux/generic/wordsize-32/fxstat64.c: New file.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/fxstatat64.c: New file.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/lxstat64.c: Make __lxstat
	an alias of __lxstat64 if XSTAT_IS_XSTAT64 is set to non-zero.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/xstat64.c: Ditto for
	__xstat.