function cflipsign( z, y ) {
	var v = addon( z, y );
	return new Complex128( v.re, v.im );
}
Returns a double-precision complex floating-point number with the same magnitude as `z` and the sign of `y*z`.

@private
@param {Complex128} z - complex number
@param {number} y - number from which to derive the sign
@returns {Complex128} result

@example
var Complex128 = require( '@stdlib/complex/float64/ctor' );
var real = require( '@stdlib/complex/float64/real' );
var imag = require( '@stdlib/complex/float64/imag' );

var v = cflipsign( new Complex128( -4.2, 5.5 ), -55.0 );
// returns <Complex128>

var re = real( v );
// returns 4.2

var im = imag( v );
// returns -5.5