No point preserving the truthy value of &&/||'s lhs
Fix memory/retain handling for register spilling
v_to_stack_mem() uses %bp not %sp, which fixes reg saving
Change how debug labels are added - octx has a last_used_block
Fix flow control for while statements
Move the backend leak check and add a description
Remove unnecessary retain/release in struct and op exprs
Stop leak of V_FLAG comparisons