For clarity, and to match the header layout. I certainly found it
easier when poking around to have this split explicit.
I don't feel like this is necessary and creating a subdirectory without creating a new library feels weird. I agree the layout is a bit weird for new comer to LTO library but it is a relatively small hurdle. I don't exactly feel like I want to pay the cost of making git blame a bit harder.
Any other reason for changing the layout?
Just what I said in the comment. I'm not wedded to this change. Will drop it if others don't think it makes sense.
Out of interest do you know if there are plans to remove the legacy code one day?
Apple is pretty much the only major user for legacy interfaces and Sony still uses it here and there. I don't think the code can be removed in the near future even all the major users move away from it because all the users of the legacy toolchains.