Revert "Define MSG_NOSIGNAL to 0 on platforms where it is unavailable."
Revert "Define MSG_NOSIGNAL to 0 on platforms where it is unavailable."

This reverts commit 6a0296791d5e81102a12a3142f5be25cb40f9825.

The change breaks build on Fedora Linux.

MidasPaymentLTD/midascoin,MidasPaymentLTD/midascoin,MidasPaymentLTD/midascoin,MidasPaymentLTD/midascoin,MidasPaymentLTD/midascoin