Revert "Check and enable -Wshadow by default."
Revert "Check and enable -Wshadow by default."

This reverts commit fd5654cab1e5d317119f747abd245c620e8ba29b.

This is still causing too many warnings for some compiler combinations,
forget it for now.

ivansib/sibcoin,thelazier/dash,ionomy/ion,biblepay/biblepay,ionomy/ion,biblepay/biblepay,ivansib/sibcoin,thelazier/dash,nmarley/dash,dashpay/dash,ionomy/ion,ivansib/sibcoin,dashpay/dash,thelazier/dash,ionomy/ion,crowning-/dash,biblepay/biblepay,biblepay/biblepay,ivansib/sibcoin,dashpay/dash,biblepay/biblepay,crowning-/dash,ionomy/ion,UdjinM6/dash,crowning-/dash,ivansib/sibcoin,nmarley/dash,ionomy/ion,biblepay/biblepay,ivansib/sibcoin,thelazier/dash,nmarley/dash,UdjinM6/dash,crowning-/dash,nmarley/dash,dashpay/dash,biblepay/biblepay,nmarley/dash,nmarley/dash,UdjinM6/dash,thelazier/dash,UdjinM6/dash,crowning-/dash,biblepay/biblepay,crowning-/dash,dashpay/dash,UdjinM6/dash,nmarley/dash