Logic for register saving
Added V_REG_SAVE and stack-dereference delay optimisation back in
Correct type-size when loading REG_SAVE values
Better compound assignment code-gen
Better float -> _Bool casts
Tidy x86_xchg_fi
Use the 'l' suffix on cvt*2* insns
Removed struct commenting
v_flag() -> v_set_flag()
Comment about float convert truncation
V_FLAG backend type has a float/ordered modifier
Redirect out_asm() for zero-assign through vstack()