Spacer falls into SIGSEGV when "get-proof" is passed

[shiatsumat]

On z3 4.8.6 I encounter the following issue.

$ z3 -in
(declare-rel ? ())
(query ?)
unsat
(get-proof)
fish: 'z3 -in' terminated by signal SIGSEGV (Address boundary error)

[NikolajBjorner]

Fort the "rel" and "query" extension syntax you want something along the lines of:

(set-option :fp.engine spacer)
(declare-rel ? ())
(query ? :print-certificate true)