Bugfix: configure: Quote SUPPRESS_WARNINGS sufficiently to preserve brackets
Bugfix: configure: Quote SUPPRESS_WARNINGS sufficiently to preserve brackets

The regex includes [/ ] which is supposed to match either a forward slash or a
space, but m4 treats the brackets as special characters and effectively strips
them out, leading to -isystem /usr/include paths except for in the typical
scenario where it is the final parameter in the flag string.

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