In bug_79_double_complex, the bitwise comparison `res1 .ne. res2` returns true on some archs (i586) though `res1` and `res2` are equal upto double precision. Instead compare the absolute value of their difference to double precision 0 which works on all archs. Fixes #269. Co-authored-by: Atri Bhattacharya <A.Bhattacharya@uliege.be>