guix: Set ZERO_AR_DATE for darwin build determinism
guix: Set ZERO_AR_DATE for darwin build determinism

See comments inserted in this commit.

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