#pragma option -Z and #pragma compat 1 difference.

[Y-Less]

The former doesn't work, the latter does. Apparently using the former can give unfound file errors. I guess the problem is that the latter does:

sym=findconst("__compat",NULL);
assert(sym!=NULL);
sym->addr=pc_compat;

While the former doesn't. Probably just requires:

sym=findconst("__compat",NULL);
if (sym)
    sym->addr=pc_compat;

Under -Z, which would account for both cases - before it is created and after.

[Y-Less]

I said "doesn't work" and "gives unfound file errors". However, I think the problem actually stems from YSI looking for __compat for certain actions. Because it is not set, the code tries to do the wrong thing for the current compile mode. So the problem is half compiler (not setting __compat) and half YSI (depending on the correct value).