PMComplex miss a signBit method (used in Pharo)

[SergeStinckwich]

In Pharo 7.0, arcTan: has been redesigned to use signBit instead of sign (in order to detect IEEE-754 negative-zero). PMComplex miss this method.

[SergeStinckwich]

The solution is to add the method :

PMComplex>>signBit
^self real signBit