Need Atmel 89C5131 microcontroler library for Altium designer v14.3.9
I assume you are looking for a schematic symbol, and perhaps footprint.  If so, you should just make the required symbols yourself - then you will know that it matches the component you are using (and, for the schematic symbol, that it has the pins arranged (and named) in a way that will suit your use.)

I don't trust other people's libraries (even Altium's - I once found an IC symbol that bore no relation to the maker's datasheet!).