build: Enable -Werror=sign-compare
build: Enable -Werror=sign-compare

Explicitly add -Wsign-compare as well - not required for all compilers, as GCC activates it
under -Wall, but may impact clang, etc.

jambolo/bitcoin,apoelstra/bitcoin,pataquets/namecoin-core,EthanHeilman/bitcoin,fanquake/bitcoin,MarcoFalke/bitcoin,domob1812/bitcoin,andreaskern/bitcoin,Xekyo/bitcoin,prusnak/bitcoin,EthanHeilman/bitcoin,sstone/bitcoin,AkioNak/bitcoin,litecoin-project/litecoin,dscotese/bitcoin,namecoin/namecore,MarcoFalke/bitcoin,mm-s/bitcoin,apoelstra/bitcoin,lateminer/bitcoin,alecalve/bitcoin,litecoin-project/litecoin,kallewoof/bitcoin,ElementsProject/elements,pstratem/bitcoin,pataquets/namecoin-core,dscotese/bitcoin,AkioNak/bitcoin,litecoin-project/litecoin,GroestlCoin/bitcoin,midnightmagic/bitcoin,jnewbery/bitcoin,ajtowns/bitcoin,bitcoinsSG/bitcoin,achow101/bitcoin,GroestlCoin/bitcoin,instagibbs/bitcoin,pstratem/bitcoin,bitcoinknots/bitcoin,instagibbs/bitcoin,jambolo/bitcoin,cdecker/bitcoin,pataquets/namecoin-core,namecoin/namecore,anditto/bitcoin,Sjors/bitcoin,JeremyRubin/bitcoin,MeshCollider/bitcoin,pstratem/bitcoin,lateminer/bitcoin,jonasschnelli/bitcoin,prusnak/bitcoin,yenliangl/bitcoin,lateminer/bitcoin,namecoin/namecoin-core,pstratem/bitcoin,namecoin/namecoin-core,midnightmagic/bitcoin,n1bor/bitcoin,cdecker/bitcoin,jamesob/bitcoin,rnicoll/bitcoin,MeshCollider/bitcoin,sipsorcery/bitcoin,sstone/bitcoin,tecnovert/particl-core,EthanHeilman/bitcoin,mm-s/bitcoin,jnewbery/bitcoin,tecnovert/particl-core,rnicoll/bitcoin,Sjors/bitcoin,GroestlCoin/GroestlCoin,sipsorcery/bitcoin,qtumproject/qtum,yenliangl/bitcoin,JeremyRubin/bitcoin,achow101/bitcoin,kallewoof/bitcoin,sipsorcery/bitcoin,bitcoinsSG/bitcoin,Sjors/bitcoin,mruddy/bitcoin,prusnak/bitcoin,rnicoll/dogecoin,bitcoinknots/bitcoin,namecoin/namecore,alecalve/bitcoin,Xekyo/bitcoin,practicalswift/bitcoin,achow101/bitcoin,namecoin/namecoin-core,ajtowns/bitcoin,domob1812/bitcoin,Xekyo/bitcoin,namecoin/namecore,rnicoll/dogecoin,sstone/bitcoin,JeremyRubin/bitcoin,kallewoof/bitcoin,bitcoin/bitcoin,domob1812/namecore,mm-s/bitcoin,particl/particl-core,JeremyRubin/bitcoin,tecnovert/particl-core,MeshCollider/bitcoin,domob1812/namecore,rnicoll/bitcoin,EthanHeilman/bitcoin,GroestlCoin/GroestlCoin,midnightmagic/bitcoin,fujicoin/fujicoin,litecoin-project/litecoin,AkioNak/bitcoin,midnightmagic/bitcoin,bitcoin/bitcoin,domob1812/bitcoin,namecoin/namecore,bitcoinsSG/bitcoin,particl/particl-core,fanquake/bitcoin,GroestlCoin/bitcoin,GroestlCoin/GroestlCoin,bitcoinknots/bitcoin,apoelstra/bitcoin,jamesob/bitcoin,jonasschnelli/bitcoin,sstone/bitcoin,rnicoll/bitcoin,MarcoFalke/bitcoin,sstone/bitcoin,bitcoin/bitcoin,alecalve/bitcoin,andreaskern/bitcoin,andreaskern/bitcoin,jamesob/bitcoin,practicalswift/bitcoin,Xekyo/bitcoin,particl/particl-core,dscotese/bitcoin,alecalve/bitcoin,EthanHeilman/bitcoin,Xekyo/bitcoin,jonasschnelli/bitcoin,rnicoll/dogecoin,n1bor/bitcoin,jlopp/statoshi,litecoin-project/litecoin,GroestlCoin/GroestlCoin,kallewoof/bitcoin,apoelstra/bitcoin,GroestlCoin/GroestlCoin,jamesob/bitcoin,andreaskern/bitcoin,dscotese/bitcoin,sstone/bitcoin,tecnovert/particl-core,domob1812/namecore,cdecker/bitcoin,ElementsProject/elements,GroestlCoin/bitcoin,fanquake/bitcoin,jlopp/statoshi,lateminer/bitcoin,practicalswift/bitcoin,jlopp/statoshi,n1bor/bitcoin,achow101/bitcoin,bitcoin/bitcoin,pstratem/bitcoin,mruddy/bitcoin,lateminer/bitcoin,jonasschnelli/bitcoin,Xekyo/bitcoin,jlopp/statoshi,ajtowns/bitcoin,namecoin/namecoin-core,domob1812/namecore,mm-s/bitcoin,apoelstra/bitcoin,mm-s/bitcoin,kallewoof/bitcoin,yenliangl/bitcoin,bitcoin/bitcoin,bitcoin/bitcoin,n1bor/bitcoin,namecoin/namecoin-core,dscotese/bitcoin,mruddy/bitcoin,sipsorcery/bitcoin,pstratem/bitcoin,AkioNak/bitcoin,jambolo/bitcoin,rnicoll/bitcoin,rnicoll/bitcoin,anditto/bitcoin,fanquake/bitcoin,instagibbs/bitcoin,bitcoinsSG/bitcoin,dscotese/bitcoin,GroestlCoin/GroestlCoin,Sjors/bitcoin,qtumproject/qtum,fanquake/bitcoin,fujicoin/fujicoin,prusnak/bitcoin,qtumproject/qtum,achow101/bitcoin,instagibbs/bitcoin,jlopp/statoshi,EthanHeilman/bitcoin,domob1812/namecore,particl/particl-core,jambolo/bitcoin,jnewbery/bitcoin,particl/particl-core,midnightmagic/bitcoin,namecoin/namecore,MarcoFalke/bitcoin,andreaskern/bitcoin,cdecker/bitcoin,MeshCollider/bitcoin,kallewoof/bitcoin,particl/particl-core,pataquets/namecoin-core,jnewbery/bitcoin,yenliangl/bitcoin,cdecker/bitcoin,ajtowns/bitcoin,fujicoin/fujicoin,domob1812/namecore,litecoin-project/litecoin,practicalswift/bitcoin,MarcoFalke/bitcoin,bitcoinsSG/bitcoin,prusnak/bitcoin,alecalve/bitcoin,rnicoll/dogecoin,ElementsProject/elements,rnicoll/dogecoin,practicalswift/bitcoin,midnightmagic/bitcoin,AkioNak/bitcoin,MeshCollider/bitcoin,domob1812/bitcoin,instagibbs/bitcoin,jlopp/statoshi,qtumproject/qtum,jamesob/bitcoin,anditto/bitcoin,instagibbs/bitcoin,domob1812/bitcoin,GroestlCoin/bitcoin,Sjors/bitcoin,andreaskern/bitcoin,fanquake/bitcoin,cdecker/bitcoin,jonasschnelli/bitcoin,jnewbery/bitcoin,mm-s/bitcoin,anditto/bitcoin,qtumproject/qtum,GroestlCoin/bitcoin,achow101/bitcoin,bitcoinsSG/bitcoin,jambolo/bitcoin,prusnak/bitcoin,anditto/bitcoin,mruddy/bitcoin,n1bor/bitcoin,anditto/bitcoin,ElementsProject/elements,fujicoin/fujicoin,mruddy/bitcoin,qtumproject/qtum,pataquets/namecoin-core,yenliangl/bitcoin,mruddy/bitcoin,MarcoFalke/bitcoin,fujicoin/fujicoin,domob1812/bitcoin,MeshCollider/bitcoin,qtumproject/qtum,ElementsProject/elements,AkioNak/bitcoin,bitcoinknots/bitcoin,practicalswift/bitcoin,bitcoinknots/bitcoin,yenliangl/bitcoin,tecnovert/particl-core,sipsorcery/bitcoin,ElementsProject/elements,jambolo/bitcoin,sipsorcery/bitcoin,jamesob/bitcoin,pataquets/namecoin-core,lateminer/bitcoin,ajtowns/bitcoin,JeremyRubin/bitcoin,ajtowns/bitcoin,fujicoin/fujicoin,JeremyRubin/bitcoin,n1bor/bitcoin,alecalve/bitcoin,apoelstra/bitcoin,namecoin/namecoin-core,tecnovert/particl-core