Do shower doors for tiled openings have to fit the width exactly?

So I just measured my cement board to cement board width and before tiling it is 4'11". This is due to the pan instructions of putting the pan 'against' the frame. The pan is cast iron covered in porcelain so I would not have to tile that.

I was thinking I could buy a standard shower door of 5" but the pan instructions screw that up. Once tile is in, I am guessing 4 foot 10.5 inches is left.

Are there 5' shower doors you just cut down and the glass overlaps more? What are some suggestions here? Last time I was at home depot, all the doors were of a fixed size.

Thanks.