isl_input.c: read_defined_var_list: avoid double free on error

[isl.git] / test_inputs / equality4.pwqp

[m,n] -> { [x,y] -> x^2 * y + m + 13 * n: n = 2x + 4y and 0 <= x,y <= 10 and 3 n = 5 m }