Had a look on mine.
The pipe looks to run from the cast section of exhaust at the back of the turbo, behind the engine block, and to the bottom of the cast pipe that has the egr valve sitting on top (the space ship thing!).
You will be losing a small amount of pressure, so maybe reduced performance, although its a tiny crack, so you probably wouldnt notice.
Looking at the pipe, its a definite crack in solid metal, doesnt look like its weakened by corrosion. Its entirely possible this is either realted to, or a result of, something vibrating - as its so solid metal at each end, i'd be looking at an engine mount allowing the crack end to move a fraction, whereas the egr valve end is held solid.
I wouldnt fancy taking it off to weld, the end you have photographed isnt so bad to get to, but the other end would need a fair bit removing, so either weld in-situ, or even one of the 'liquid metal' types products, but you need to sort the cause first, otherwise it'll happen again.
Cheers
Pete