use RESIZABLE_JSVARS for other boards than linux ?

So far I've only used RESIZABLE_JSVARS on Linux - otherwise you have to build in malloc/free/etc which we don't currently do (and it hurts performance).

If you want 3 distinct blocks I'd add jsVars2/jsVars3 arrays where you want them and then make your own jsvGetAddressOf function. I think the only other thing you need to worry about is in jsvNewFlatStringOfLength where there's currently an RESIZABLE_JSVARS ifdef - and you need to ensure that gets added.