i do not agree with veigar top, however you still need CDR to farm effectively so that has to be your first item.
id say buy a frozen heart first but he has no base health pool invalidating armor as a good buy.
so realistically that you're top lane, you're probably against someone who is going to dive you, that would mean you could rush
and they'll be in range for the bonus 10% quite often. you will need CDR from runes to work this. you could build morello as a first item for a better buy option, but then you're just AP top.
finally you're going to get camped, a lot, you have to play super passive when you dont have E available.
TBH he really needs a full build to have any sort of tank/bulk properties, he just doesn't have it in his bases. being that gold hungry and item dependent is not something you want to do.