OS X: use FSGetVolumeParms when targeting 10.5+.
PBHGetVolParmsSync() is not available when building with 64bit. The replacement
FSGetVolumeParms() is available on 10.5+ only. Use the latter when building
with target version 10.5+. This requires builds targeting 10.4 to 32bit and
allows building as 64bit when targeting 10.5+.
Change-Id: Ic53217f3090147bea473613335f9482623a470bd