Fix build of Gulden-tx
Fix build of Gulden-tx

Gulden-tx would not build because of dependencies caused by alert.cpp
Moved alert.cpp to server sources to fix it (tested that all binaries build with this).
nlgcoin/guldencoin-official,nlgcoin/guldencoin-official,nlgcoin/guldencoin-official,nlgcoin/guldencoin-official,nlgcoin/guldencoin-official,nlgcoin/guldencoin-official