At all.
Even taking contractual position instead of copyright doesn't change the part where it does not matter nothing regarding whether you link or not with GPLed code that is established by the text of the GPL.
What's important, and what RMS used to bully projects in the past into changing licenses, is whether the work would be considered derivative - as in, would it exist without inclusiom of GPLed code? (Very simplified depiction - in practice that's something a court would have to decide).
At the same time it means that if you use a GPLed library that just implements an otherwise existing interface and it's completely conceivable that your code isn't derived from it, then it doesn't matter that you linked. But it can also mean that just separating with a network connection also isn't enough to break derivative-ness.