As was introduced in 96 core, the line of sight could be achieved thru windows and noblock tiles, still sometimes it's needed to have old-type LOS. For example, it's rather annoying to see players teleporting through windows and getting places were they shouldn't and killing monsters through fence with long spear. I could turn off the new type los, but then again it works better in cheking if vendor has line of sight over mobile, or for anatomy, detect hidden targets and many other.

LOS functions should take flag LOS_GOOD_VIEW and LOS_SMALL_VIEW.