util: enable hardlink for some BSD-family filesystems Since we can now detect filesystems on FreeBSD and OSX. Add their major filesystems (ufs, zfs for FreeBSD; hfs for OSX) to the hardlink whitelist.

osutil: report fstype for BSD and OSX

setup: use a more strict way to test BSD or OSX's statfs We want to use the `f_fstypename` field to get the filesystem type. Test it directly. The new macro HAVE_BSD_STATFS implys the old HAVE_SYS_MOUNT_H and HAVE_SYS_PARAM_H. So the latter ones are removed.