Use approximate comparison between the result of __divsc3()

and the canonical value calculated, to allow the possible difference of

1 representable value resulting from optimization.

For example, the value of (0.000001+j0.000001) / (-0.500000-j2.000000))

computed the canonical way without specific machine flags is:

z = -0x1.3bce70p-21 + j0x1.7af7bcp-22

However, if -march=i386 -mfpmath=387 is used, it becomes:

z = -0x1.3bce72p-21 + j0x1.7af7bcp-22

While this difference is insignificant, it may cause the exact

comparison used in tests to fail. Allowing the difference of one

representable value seems to be a reasonable compromise.