build: remove boost dep from libmultiprocess
build: remove boost dep from libmultiprocess

Looks like this hasn't been needed since
https://github.com/chaincodelabs/libmultiprocess/pull/25 and was just
missed in #19160.

ajtowns/bitcoin,AkioNak/bitcoin,lateminer/bitcoin,AkioNak/bitcoin,Xekyo/bitcoin,pataquets/namecoin-core,particl/particl-core,kallewoof/bitcoin,sipsorcery/bitcoin,dscotese/bitcoin,achow101/bitcoin,domob1812/bitcoin,jamesob/bitcoin,particl/particl-core,lateminer/bitcoin,namecoin/namecore,achow101/bitcoin,GroestlCoin/bitcoin,GroestlCoin/GroestlCoin,anditto/bitcoin,jamesob/bitcoin,Xekyo/bitcoin,namecoin/namecore,GroestlCoin/GroestlCoin,namecoin/namecoin-core,anditto/bitcoin,jamesob/bitcoin,Xekyo/bitcoin,bitcoinknots/bitcoin,GroestlCoin/GroestlCoin,instagibbs/bitcoin,anditto/bitcoin,bitcoinknots/bitcoin,sstone/bitcoin,lateminer/bitcoin,sipsorcery/bitcoin,sipsorcery/bitcoin,Xekyo/bitcoin,domob1812/bitcoin,fanquake/bitcoin,mruddy/bitcoin,bitcoinsSG/bitcoin,pataquets/namecoin-core,jlopp/statoshi,particl/particl-core,sstone/bitcoin,tecnovert/particl-core,bitcoinknots/bitcoin,jlopp/statoshi,ajtowns/bitcoin,dscotese/bitcoin,ajtowns/bitcoin,fanquake/bitcoin,fujicoin/fujicoin,AkioNak/bitcoin,bitcoinknots/bitcoin,namecoin/namecore,kallewoof/bitcoin,namecoin/namecoin-core,jamesob/bitcoin,GroestlCoin/bitcoin,achow101/bitcoin,andreaskern/bitcoin,jlopp/statoshi,domob1812/bitcoin,bitcoinsSG/bitcoin,namecoin/namecore,sipsorcery/bitcoin,lateminer/bitcoin,fujicoin/fujicoin,namecoin/namecoin-core,GroestlCoin/GroestlCoin,bitcoinsSG/bitcoin,dscotese/bitcoin,mruddy/bitcoin,andreaskern/bitcoin,achow101/bitcoin,ajtowns/bitcoin,jlopp/statoshi,andreaskern/bitcoin,kallewoof/bitcoin,bitcoin/bitcoin,namecoin/namecoin-core,bitcoin/bitcoin,jambolo/bitcoin,fanquake/bitcoin,mruddy/bitcoin,lateminer/bitcoin,pataquets/namecoin-core,pataquets/namecoin-core,instagibbs/bitcoin,particl/particl-core,bitcoinknots/bitcoin,sipsorcery/bitcoin,jlopp/statoshi,ajtowns/bitcoin,bitcoinsSG/bitcoin,bitcoinsSG/bitcoin,jambolo/bitcoin,lateminer/bitcoin,ajtowns/bitcoin,AkioNak/bitcoin,jambolo/bitcoin,domob1812/bitcoin,achow101/bitcoin,dscotese/bitcoin,jamesob/bitcoin,jlopp/statoshi,kallewoof/bitcoin,namecoin/namecoin-core,domob1812/bitcoin,anditto/bitcoin,particl/particl-core,fanquake/bitcoin,jambolo/bitcoin,instagibbs/bitcoin,tecnovert/particl-core,sstone/bitcoin,sstone/bitcoin,instagibbs/bitcoin,instagibbs/bitcoin,dscotese/bitcoin,bitcoin/bitcoin,andreaskern/bitcoin,sstone/bitcoin,andreaskern/bitcoin,tecnovert/particl-core,namecoin/namecore,particl/particl-core,instagibbs/bitcoin,mruddy/bitcoin,Xekyo/bitcoin,bitcoin/bitcoin,GroestlCoin/bitcoin,GroestlCoin/bitcoin,sipsorcery/bitcoin,sstone/bitcoin,GroestlCoin/GroestlCoin,tecnovert/particl-core,andreaskern/bitcoin,pataquets/namecoin-core,anditto/bitcoin,jambolo/bitcoin,pataquets/namecoin-core,fujicoin/fujicoin,domob1812/bitcoin,fujicoin/fujicoin,mruddy/bitcoin,tecnovert/particl-core,bitcoin/bitcoin,kallewoof/bitcoin,dscotese/bitcoin,namecoin/namecore,GroestlCoin/bitcoin,jambolo/bitcoin,fujicoin/fujicoin,GroestlCoin/bitcoin,GroestlCoin/GroestlCoin,Xekyo/bitcoin,namecoin/namecoin-core,mruddy/bitcoin,jamesob/bitcoin,kallewoof/bitcoin,anditto/bitcoin,fanquake/bitcoin,bitcoin/bitcoin,bitcoinsSG/bitcoin,achow101/bitcoin,fujicoin/fujicoin,AkioNak/bitcoin,fanquake/bitcoin,tecnovert/particl-core,AkioNak/bitcoin