Be more precise in p6_to_p5 signatures
Be more precise in p6_to_p5 signatures

all undefined values should result in undef; the type-specific code only works for defined values,
not for the type objects

niner/Inline-Perl5,FROGGS/Inline-Perl5,hoelzro/Inline-Perl5,niner/Inline-Perl5,FROGGS/Inline-Perl5,hoelzro/Inline-Perl5,hoelzro/Inline-Perl5