Oracle.c:1535:14: error: 'sv_undef' undeclared (first use in this function

I think this happens because 'sv_undef' has been removed from the API and replaced with &PL_sv_undef.
Same goes for 'sv_yes' (now '&PL_sv_yes') and 'sv_no' (now '&PL_sv_no').

I think (untested) you'll get around that problem by prepending (in Oracle.xs) all sv_undef/sv_yes/sv_no occurrences with '&PL_'.

Cheers,
Rob