If your door is a "Tri-mark" and the striker bolt breaks.
Well I'd love to give you my opinion of that design but alas melting monitors is not good.
Take the broken striker bolt to a metal smith I've used 3 of 'em over the years (Same for basement latches) Runs 25-40 bucks (Cheaper than a new latch) to have 'em carve one out of steel.
First was a body shop (Basewment latch) 2nd was a welder (Door) 3rd was Seneca Engineering, Senect South Carolina, (Basement again) of the 3 the last did a fantastic job.
Steel is much harder to break than the pot metal Tri-Mark used.