depends: fix libzmq's needless linking against libstdc++
depends: fix libzmq's needless linking against libstdc++

This is broken for a number of reasons, including:
- g++ understands "-static-libstdc++ -lstdc++" to mean "link against whatever
  libstdc++ exists, probably shared", which in itself is buggy.
- another stdlib (libc++ for example) may be in use

apoelstra/bitcoin,ElementsProject/elements,bespike/litecoin,sipsorcery/bitcoin,starwels/starwels,sstone/bitcoin,DigitalPandacoin/pandacoin,sstone/bitcoin,droark/bitcoin,kallewoof/bitcoin,domob1812/bitcoin,guncoin/guncoin,GlobalBoost/GlobalBoost,yenliangl/bitcoin,namecoin/namecore,Bushstar/UFO-Project,CryptArc/bitcoin,donaloconnor/bitcoin,FeatherCoin/Feathercoin,pataquets/namecoin-core,untrustbank/litecoin,bitcoin/bitcoin,RHavar/bitcoin,prusnak/bitcoin,particl/particl-core,kazcw/bitcoin,starwels/starwels,joshrabinowitz/bitcoin,bitcoinsSG/bitcoin,GroestlCoin/bitcoin,Kogser/bitcoin,GroestlCoin/bitcoin,ppcoin/ppcoin,fujicoin/fujicoin,anditto/bitcoin,jnewbery/bitcoin,domob1812/namecore,mb300sd/bitcoin,ryanofsky/bitcoin,litecoin-project/litecoin,particl/particl-core,globaltoken/globaltoken,DigitalPandacoin/pandacoin,Christewart/bitcoin,litecoin-project/litecoin,monacoinproject/monacoin,myriadcoin/myriadcoin,Bushstar/UFO-Project,achow101/bitcoin,yenliangl/bitcoin,litecoin-project/litecoin,lbryio/lbrycrd,ericshawlinux/bitcoin,donaloconnor/bitcoin,EthanHeilman/bitcoin,sebrandon1/bitcoin,sebrandon1/bitcoin,sebrandon1/bitcoin,GroestlCoin/GroestlCoin,namecoin/namecoin-core,bitcoinsSG/bitcoin,mitchellcash/bitcoin,viacoin/viacoin,OmniLayer/omnicore,wellenreiter01/Feathercoin,jmcorgan/bitcoin,practicalswift/bitcoin,dscotese/bitcoin,Christewart/bitcoin,laudaa/bitcoin,alecalve/bitcoin,monacoinproject/monacoin,OmniLayer/omnicore,ajtowns/bitcoin,domob1812/huntercore,globaltoken/globaltoken,nikkitan/bitcoin,anditto/bitcoin,gjhiggins/vcoincore,wellenreiter01/Feathercoin,h4x3rotab/BTCGPU,practicalswift/bitcoin,rnicoll/bitcoin,mitchellcash/bitcoin,andreaskern/bitcoin,thrasher-/litecoin,myriadcoin/myriadcoin,litecoin-project/litecoin,n1bor/bitcoin,namecoin/namecore,ahmedbodi/vertcoin,tecnovert/particl-core,JeremyRubin/bitcoin,DigitalPandacoin/pandacoin,peercoin/peercoin,ahmedbodi/vertcoin,apoelstra/bitcoin,Kogser/bitcoin,deeponion/deeponion,ahmedbodi/vertcoin,droark/bitcoin,r8921039/bitcoin,MeshCollider/bitcoin,Xekyo/bitcoin,BTCGPU/BTCGPU,MarcoFalke/bitcoin,jambolo/bitcoin,joshrabinowitz/bitcoin,practicalswift/bitcoin,gjhiggins/vcoincore,Sjors/bitcoin,n1bor/bitcoin,vmp32k/litecoin,tjps/bitcoin,ajtowns/bitcoin,AkioNak/bitcoin,GroestlCoin/bitcoin,sstone/bitcoin,lateminer/bitcoin,myriadteam/myriadcoin,1185/starwels,ahmedbodi/vertcoin,TheBlueMatt/bitcoin,digibyte/digibyte,n1bor/bitcoin,MarcoFalke/bitcoin,r8921039/bitcoin,mitchellcash/bitcoin,rawodb/bitcoin,rnicoll/dogecoin,yenliangl/bitcoin,MarcoFalke/bitcoin,jtimon/bitcoin,randy-waterhouse/bitcoin,pstratem/bitcoin,domob1812/namecore,ElementsProject/elements,sipsorcery/bitcoin,domob1812/huntercore,wellenreiter01/Feathercoin,starwels/starwels,myriadcoin/myriadcoin,qtumproject/qtum,Christewart/bitcoin,MazaCoin/maza,mruddy/bitcoin,qtumproject/qtum,afk11/bitcoin,pstratem/bitcoin,myriadteam/myriadcoin,digibyte/digibyte,cdecker/bitcoin,pataquets/namecoin-core,lbryio/lbrycrd,midnightmagic/bitcoin,mb300sd/bitcoin,rnicoll/dogecoin,bitcoinsSG/bitcoin,namecoin/namecoin-core,myriadcoin/myriadcoin,bespike/litecoin,brandonrobertz/namecoin-core,monacoinproject/monacoin,deeponion/deeponion,randy-waterhouse/bitcoin,bitcoinsSG/bitcoin,wellenreiter01/Feathercoin,FeatherCoin/Feathercoin,andreaskern/bitcoin,maaku/bitcoin,qtumproject/qtum,BTCGPU/BTCGPU,alecalve/bitcoin,EthanHeilman/bitcoin,maaku/bitcoin,mruddy/bitcoin,midnightmagic/bitcoin,FeatherCoin/Feathercoin,Xekyo/bitcoin,prusnak/bitcoin,fujicoin/fujicoin,globaltoken/globaltoken,tecnovert/particl-core,kallewoof/bitcoin,MazaCoin/maza,ajtowns/bitcoin,Kogser/bitcoin,alecalve/bitcoin,myriadteam/myriadcoin,ericshawlinux/bitcoin,kallewoof/bitcoin,domob1812/bitcoin,droark/bitcoin,GlobalBoost/GlobalBoost,jamesob/bitcoin,kazcw/bitcoin,sebrandon1/bitcoin,sebrandon1/bitcoin,Flowdalic/bitcoin,jonasschnelli/bitcoin,Flowdalic/bitcoin,paveljanik/bitcoin,donaloconnor/bitcoin,droark/bitcoin,domob1812/bitcoin,tjps/bitcoin,cdecker/bitcoin,alecalve/bitcoin,r8921039/bitcoin,fujicoin/fujicoin,yenliangl/bitcoin,MeshCollider/bitcoin,deeponion/deeponion,Bushstar/UFO-Project,gjhiggins/vcoincore,jambolo/bitcoin,particl/particl-core,viacoin/viacoin,TheBlueMatt/bitcoin,EthanHeilman/bitcoin,Kogser/bitcoin,joshrabinowitz/bitcoin,qtumproject/qtum,namecoin/namecoin-core,rnicoll/dogecoin,mruddy/bitcoin,midnightmagic/bitcoin,rawodb/bitcoin,Bushstar/UFO-Project,peercoin/peercoin,jlopp/statoshi,bitcoinknots/bitcoin,TheBlueMatt/bitcoin,domob1812/huntercore,mm-s/bitcoin,TheBlueMatt/bitcoin,globaltoken/globaltoken,randy-waterhouse/bitcoin,deeponion/deeponion,rnicoll/bitcoin,stamhe/bitcoin,practicalswift/bitcoin,prusnak/bitcoin,ElementsProject/elements,TheBlueMatt/bitcoin,jamesob/bitcoin,AkioNak/bitcoin,vertcoin/vertcoin,Kogser/bitcoin,n1bor/bitcoin,bitcoinknots/bitcoin,thrasher-/litecoin,brandonrobertz/namecoin-core,Bushstar/UFO-Project,GroestlCoin/GroestlCoin,GlobalBoost/GlobalBoost,lateminer/bitcoin,donaloconnor/bitcoin,CryptArc/bitcoin,jlopp/statoshi,digibyte/digibyte,jtimon/bitcoin,peercoin/peercoin,jnewbery/bitcoin,MarcoFalke/bitcoin,stamhe/bitcoin,mitchellcash/bitcoin,rnicoll/bitcoin,untrustbank/litecoin,vertcoin/vertcoin,mb300sd/bitcoin,litecoin-project/litecoin,bitcoin/bitcoin,RHavar/bitcoin,kallewoof/bitcoin,Flowdalic/bitcoin,peercoin/peercoin,JeremyRubin/bitcoin,jambolo/bitcoin,tecnovert/particl-core,mruddy/bitcoin,vertcoin/vertcoin,fanquake/bitcoin,CryptArc/bitcoin,afk11/bitcoin,mitchellcash/bitcoin,Sjors/bitcoin,domob1812/namecore,GroestlCoin/bitcoin,qtumproject/qtum,ericshawlinux/bitcoin,laudaa/bitcoin,Kogser/bitcoin,dscotese/bitcoin,1185/starwels,RHavar/bitcoin,lbryio/lbrycrd,Xekyo/bitcoin,BTCGPU/BTCGPU,mb300sd/bitcoin,myriadteam/myriadcoin,vertcoin/vertcoin,AkioNak/bitcoin,GroestlCoin/GroestlCoin,afk11/bitcoin,litecoin-project/litecoin,rnicoll/dogecoin,starwels/starwels,bitcoin/bitcoin,jonasschnelli/bitcoin,brandonrobertz/namecoin-core,kallewoof/bitcoin,afk11/bitcoin,jambolo/bitcoin,midnightmagic/bitcoin,prusnak/bitcoin,jnewbery/bitcoin,ericshawlinux/bitcoin,monacoinproject/monacoin,andreaskern/bitcoin,fujicoin/fujicoin,ppcoin/ppcoin,cdecker/bitcoin,jlopp/statoshi,andreaskern/bitcoin,jmcorgan/bitcoin,namecoin/namecore,sipsorcery/bitcoin,DigitalPandacoin/pandacoin,Kogser/bitcoin,paveljanik/bitcoin,cdecker/bitcoin,ajtowns/bitcoin,Kogser/bitcoin,pataquets/namecoin-core,rnicoll/bitcoin,namecoin/namecore,lateminer/bitcoin,wellenreiter01/Feathercoin,bitcoinsSG/bitcoin,yenliangl/bitcoin,ryanofsky/bitcoin,wellenreiter01/Feathercoin,qtumproject/qtum,thrasher-/litecoin,pstratem/bitcoin,ryanofsky/bitcoin,apoelstra/bitcoin,EthanHeilman/bitcoin,globaltoken/globaltoken,monacoinproject/monacoin,Kogser/bitcoin,dscotese/bitcoin,ryanofsky/bitcoin,vmp32k/litecoin,fujicoin/fujicoin,vmp32k/litecoin,laudaa/bitcoin,particl/particl-core,stamhe/bitcoin,peercoin/peercoin,instagibbs/bitcoin,jmcorgan/bitcoin,CryptArc/bitcoin,tecnovert/particl-core,myriadteam/myriadcoin,namecoin/namecoin-core,rnicoll/bitcoin,kazcw/bitcoin,h4x3rotab/BTCGPU,namecoin/namecore,vertcoin/vertcoin,jlopp/statoshi,ryanofsky/bitcoin,MeshCollider/bitcoin,FeatherCoin/Feathercoin,deeponion/deeponion,donaloconnor/bitcoin,lbryio/lbrycrd,Flowdalic/bitcoin,RHavar/bitcoin,jamesob/bitcoin,Kogser/bitcoin,jambolo/bitcoin,OmniLayer/omnicore,monacoinproject/monacoin,Sjors/bitcoin,maaku/bitcoin,achow101/bitcoin,1185/starwels,GlobalBoost/GlobalBoost,andreaskern/bitcoin,h4x3rotab/BTCGPU,myriadcoin/myriadcoin,apoelstra/bitcoin,mm-s/bitcoin,paveljanik/bitcoin,EthanHeilman/bitcoin,viacoin/viacoin,sstone/bitcoin,untrustbank/litecoin,Flowdalic/bitcoin,tecnovert/particl-core,sebrandon1/bitcoin,lbryio/lbrycrd,JeremyRubin/bitcoin,cdecker/bitcoin,namecoin/namecore,laudaa/bitcoin,fanquake/bitcoin,EthanHeilman/bitcoin,guncoin/guncoin,paveljanik/bitcoin,GroestlCoin/GroestlCoin,domob1812/bitcoin,pataquets/namecoin-core,jmcorgan/bitcoin,domob1812/namecore,vmp32k/litecoin,Xekyo/bitcoin,fujicoin/fujicoin,pstratem/bitcoin,RHavar/bitcoin,apoelstra/bitcoin,jlopp/statoshi,JeremyRubin/bitcoin,laudaa/bitcoin,digibyte/digibyte,nikkitan/bitcoin,nikkitan/bitcoin,guncoin/guncoin,MazaCoin/maza,Christewart/bitcoin,bespike/litecoin,Christewart/bitcoin,ppcoin/ppcoin,globaltoken/globaltoken,viacoin/viacoin,jtimon/bitcoin,h4x3rotab/BTCGPU,fanquake/bitcoin,sstone/bitcoin,GlobalBoost/GlobalBoost,ElementsProject/elements,cdecker/bitcoin,anditto/bitcoin,paveljanik/bitcoin,domob1812/namecore,GlobalBoost/GlobalBoost,rnicoll/dogecoin,pataquets/namecoin-core,jnewbery/bitcoin,jonasschnelli/bitcoin,ericshawlinux/bitcoin,GlobalBoost/GlobalBoost,lbryio/lbrycrd,ElementsProject/elements,laudaa/bitcoin,OmniLayer/omnicore,gjhiggins/vcoincore,achow101/bitcoin,bitcoinknots/bitcoin,peercoin/peercoin,randy-waterhouse/bitcoin,bespike/litecoin,fanquake/bitcoin,tjps/bitcoin,ajtowns/bitcoin,rawodb/bitcoin,bitcoinknots/bitcoin,midnightmagic/bitcoin,rnicoll/bitcoin,paveljanik/bitcoin,maaku/bitcoin,namecoin/namecoin-core,droark/bitcoin,bitcoinsSG/bitcoin,mb300sd/bitcoin,lateminer/bitcoin,rawodb/bitcoin,MeshCollider/bitcoin,1185/starwels,domob1812/huntercore,Christewart/bitcoin,Flowdalic/bitcoin,kazcw/bitcoin,Sjors/bitcoin,fanquake/bitcoin,bespike/litecoin,mm-s/bitcoin,rawodb/bitcoin,mitchellcash/bitcoin,ajtowns/bitcoin,ppcoin/ppcoin,r8921039/bitcoin,joshrabinowitz/bitcoin,lbryio/lbrycrd,gjhiggins/vcoincore,untrustbank/litecoin,practicalswift/bitcoin,tjps/bitcoin,lateminer/bitcoin,particl/particl-core,lateminer/bitcoin,dscotese/bitcoin,RHavar/bitcoin,kazcw/bitcoin,bitcoin/bitcoin,GroestlCoin/GroestlCoin,jtimon/bitcoin,particl/particl-core,jlopp/statoshi,myriadcoin/myriadcoin,domob1812/huntercore,mm-s/bitcoin,dscotese/bitcoin,midnightmagic/bitcoin,rawodb/bitcoin,starwels/starwels,pstratem/bitcoin,prusnak/bitcoin,brandonrobertz/namecoin-core,jmcorgan/bitcoin,CryptArc/bitcoin,mb300sd/bitcoin,h4x3rotab/BTCGPU,TheBlueMatt/bitcoin,AkioNak/bitcoin,JeremyRubin/bitcoin,kallewoof/bitcoin,AkioNak/bitcoin,jmcorgan/bitcoin,thrasher-/litecoin,mm-s/bitcoin,ElementsProject/elements,OmniLayer/omnicore,ericshawlinux/bitcoin,domob1812/bitcoin,myriadteam/myriadcoin,nikkitan/bitcoin,sipsorcery/bitcoin,digibyte/digibyte,Xekyo/bitcoin,DigitalPandacoin/pandacoin,mruddy/bitcoin,droark/bitcoin,andreaskern/bitcoin,donaloconnor/bitcoin,domob1812/namecore,jnewbery/bitcoin,r8921039/bitcoin,domob1812/huntercore,ryanofsky/bitcoin,Bushstar/UFO-Project,bitcoinknots/bitcoin,viacoin/viacoin,anditto/bitcoin,practicalswift/bitcoin,prusnak/bitcoin,afk11/bitcoin,BTCGPU/BTCGPU,dscotese/bitcoin,anditto/bitcoin,fanquake/bitcoin,tjps/bitcoin,achow101/bitcoin,achow101/bitcoin,apoelstra/bitcoin,bespike/litecoin,jambolo/bitcoin,guncoin/guncoin,jonasschnelli/bitcoin,MarcoFalke/bitcoin,BTCGPU/BTCGPU,joshrabinowitz/bitcoin,vmp32k/litecoin,pstratem/bitcoin,yenliangl/bitcoin,n1bor/bitcoin,randy-waterhouse/bitcoin,sipsorcery/bitcoin,sstone/bitcoin,afk11/bitcoin,instagibbs/bitcoin,OmniLayer/omnicore,jamesob/bitcoin,DigitalPandacoin/pandacoin,stamhe/bitcoin,namecoin/namecoin-core,GroestlCoin/bitcoin,alecalve/bitcoin,viacoin/viacoin,thrasher-/litecoin,1185/starwels,achow101/bitcoin,untrustbank/litecoin,jamesob/bitcoin,jtimon/bitcoin,bitcoin/bitcoin,instagibbs/bitcoin,gjhiggins/vcoincore,nikkitan/bitcoin,jamesob/bitcoin,JeremyRubin/bitcoin,tecnovert/particl-core,vmp32k/litecoin,vertcoin/vertcoin,randy-waterhouse/bitcoin,instagibbs/bitcoin,thrasher-/litecoin,GroestlCoin/GroestlCoin,MazaCoin/maza,jonasschnelli/bitcoin,stamhe/bitcoin,maaku/bitcoin,n1bor/bitcoin,MeshCollider/bitcoin,starwels/starwels,untrustbank/litecoin,ahmedbodi/vertcoin,mruddy/bitcoin,sipsorcery/bitcoin,Kogser/bitcoin,maaku/bitcoin,kazcw/bitcoin,ahmedbodi/vertcoin,MarcoFalke/bitcoin,FeatherCoin/Feathercoin,deeponion/deeponion,joshrabinowitz/bitcoin,1185/starwels,digibyte/digibyte,jtimon/bitcoin,anditto/bitcoin,r8921039/bitcoin,CryptArc/bitcoin,BTCGPU/BTCGPU,mm-s/bitcoin,AkioNak/bitcoin,nikkitan/bitcoin,h4x3rotab/BTCGPU,MeshCollider/bitcoin,instagibbs/bitcoin,FeatherCoin/Feathercoin,Sjors/bitcoin,bitcoin/bitcoin,tjps/bitcoin,qtumproject/qtum,MazaCoin/maza,brandonrobertz/namecoin-core,Kogser/bitcoin,domob1812/bitcoin,alecalve/bitcoin,instagibbs/bitcoin,guncoin/guncoin,MazaCoin/maza,guncoin/guncoin,stamhe/bitcoin,Xekyo/bitcoin,GroestlCoin/bitcoin,brandonrobertz/namecoin-core,pataquets/namecoin-core