*Risk everything (4,4)
'risk everything' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for go for broke that I've seen before include "Make all-or-nothing effort" , "Gamble everything" , "Risk everything in an all-out effort" , "Make an all-out effort" .)
(Other definitions for goal line that I've seen before include "Mark behind the keeper" , "End of a football pitch" , "A lion leg (anag.)" .)