Add an assert to opts::set_opts.
Add an assert to opts::set_opts.

This function leaks if called more than once.

nick-thompson/servo,anthgur/servo,splav/servo,rixrix/servo,g-k/servo,notriddle/servo,kindersung/servo,upsuper/servo,g-k/servo,fiji-flo/servo,s142857/servo,vks/servo,rentongzhang/servo,s142857/servo,mdibaiee/servo,ryancanhelpyou/servo,brendandahl/servo,akosel/servo,cbrewster/servo,brendandahl/servo,avadacatavra/servo,tschneidereit/servo,meh/servo,dati91/servo,saneyuki/servo,aweinstock314/servo,CJ8664/servo,nrc/servo,szeged/servo,aidanhs/servo,DominoTree/servo,mdibaiee/servo,ConnorGBrewster/servo,pyfisch/servo,jgraham/servo,jgraham/servo,ryancanhelpyou/servo,mt2d2/servo,aweinstock314/servo,mbrubeck/servo,j3parker/servo,vks/servo,emilio/servo,vks/servo,splav/servo,vks/servo,jlegendary/servo,larsbergstrom/servo,KiChjang/servo,KiChjang/servo,eddyb/servo,anthgur/servo,rnestler/servo,pgonda/servo,codemac/servo,szeged/servo,nnethercote/servo,szeged/servo,SimonSapin/servo,rnestler/servo,SimonSapin/servo,ConnorGBrewster/servo,eddyb/servo,dsandeephegde/servo,rentongzhang/servo,emilio/servo,karlito40/servo,sadmansk/servo,A-deLuna/servo,DominoTree/servo,dati91/servo,WriterOfAlicrow/servo,KiChjang/servo,aidanhs/servo,avadacatavra/servo,paulrouget/servo,thiagopnts/servo,SimonSapin/servo,deokjinkim/servo,thiagopnts/servo,notriddle/servo,canaltinova/servo,samfoo/servo,aweinstock314/servo,boghison/servo,wartman4404/servo,peterjoel/servo,saneyuki/servo,rnestler/servo,caldwell/servo,codemac/servo,saratang/servo,WriterOfAlicrow/servo,rentongzhang/servo,emilio/servo,eddyb/servo,WriterOfAlicrow/servo,zhangjunlei26/servo,dsandeephegde/servo,paulrouget/servo,boghison/servo,vks/servo,nerith/servo,runarberg/servo,nnethercote/servo,nrc/servo,szeged/servo,zhangjunlei26/servo,wartman4404/servo,j3parker/servo,larsbergstrom/servo,nnethercote/servo,canaltinova/servo,anthgur/servo,samfoo/servo,zentner-kyle/servo,mdibaiee/servo,meh/servo,tschneidereit/servo,tschneidereit/servo,runarberg/servo,dhananjay92/servo,A-deLuna/servo,caldwell/servo,splav/servo,upsuper/servo,KiChjang/servo,canaltinova/servo,kindersung/servo,notriddle/servo,steveklabnik/servo,jimberlage/servo,tempbottle/servo,cbrewster/servo,emilio/servo,avadacatavra/servo,rnestler/servo,youprofit/servo,g-k/servo,dvberkel/servo,j3parker/servo,saneyuki/servo,dsandeephegde/servo,peterjoel/servo,szeged/servo,peterjoel/servo,SimonSapin/servo,huonw/servo,rentongzhang/servo,kindersung/servo,s142857/servo,karlito40/servo,CJ8664/servo,saneyuki/servo,notriddle/servo,nick-thompson/servo,eddyb/servo,SimonSapin/servo,codemac/servo,szeged/servo,dagnir/servo,jdramani/servo,SimonSapin/servo,akosel/servo,rixrix/servo,akosel/servo,pgonda/servo,paulrouget/servo,nick-thompson/servo,paulrouget/servo,rentongzhang/servo,szeged/servo,tschneidereit/servo,thiagopnts/servo,caldwell/servo,dvberkel/servo,DominoTree/servo,karlito40/servo,hyowon/servo,huonw/servo,DominoTree/servo,pyfisch/servo,deokjinkim/servo,zhangjunlei26/servo,dati91/servo,rnestler/servo,CJ8664/servo,AnthonyBroadCrawford/servo,runarberg/servo,s142857/servo,hyowon/servo,emilio/servo,aidanhs/servo,rixrix/servo,rnestler/servo,cbrewster/servo,A-deLuna/servo,upsuper/servo,eddyb/servo,tempbottle/servo,larsbergstrom/servo,anthgur/servo,SimonSapin/servo,szeged/servo,rixrix/servo,deokjinkim/servo,j3parker/servo,rnestler/servo,peterjoel/servo,pyfisch/servo,larsbergstrom/servo,bjwbell/servo,tempbottle/servo,rnestler/servo,brendandahl/servo,jimberlage/servo,fiji-flo/servo,GyrosOfWar/servo,mbrubeck/servo,jdramani/servo,ConnorGBrewster/servo,fiji-flo/servo,pgonda/servo,upsuper/servo,tschneidereit/servo,anthgur/servo,akosel/servo,steveklabnik/servo,huonw/servo,nick-thompson/servo,jgraham/servo,dsandeephegde/servo,GreenRecycleBin/servo,zhangjunlei26/servo,bjwbell/servo,peterjoel/servo,kindersung/servo,sadmansk/servo,samfoo/servo,jlegendary/servo,deokjinkim/servo,cbrewster/servo,jimberlage/servo,huonw/servo,tafia/servo,ConnorGBrewster/servo,caldwell/servo,rentongzhang/servo,steveklabnik/servo,paulrouget/servo,vks/servo,WriterOfAlicrow/servo,pgonda/servo,mdibaiee/servo,s142857/servo,mattnenterprise/servo,nnethercote/servo,samfoo/servo,notriddle/servo,mdibaiee/servo,GyrosOfWar/servo,karlito40/servo,WriterOfAlicrow/servo,dagnir/servo,jdramani/servo,dati91/servo,saneyuki/servo,boghison/servo,larsbergstrom/servo,GreenRecycleBin/servo,dvberkel/servo,cbrewster/servo,karlito40/servo,dagnir/servo,aidanhs/servo,GreenRecycleBin/servo,splav/servo,tafia/servo,notriddle/servo,DominoTree/servo,j3parker/servo,AnthonyBroadCrawford/servo,pyfisch/servo,tschneidereit/servo,nnethercote/servo,thiagopnts/servo,nerith/servo,karlito40/servo,larsbergstrom/servo,paulrouget/servo,peterjoel/servo,walac/servo,rixrix/servo,hyowon/servo,upsuper/servo,nick-thompson/servo,dhananjay92/servo,CJ8664/servo,brendandahl/servo,notriddle/servo,rixrix/servo,walac/servo,mt2d2/servo,bjwbell/servo,dsandeephegde/servo,splav/servo,anthgur/servo,hyowon/servo,splav/servo,steveklabnik/servo,steveklabnik/servo,deokjinkim/servo,jdramani/servo,zentner-kyle/servo,saneyuki/servo,saratang/servo,GreenRecycleBin/servo,dsandeephegde/servo,dvberkel/servo,zhangjunlei26/servo,upsuper/servo,saneyuki/servo,saratang/servo,canaltinova/servo,jlegendary/servo,CJ8664/servo,pyfisch/servo,jlegendary/servo,bjwbell/servo,splav/servo,canaltinova/servo,emilio/servo,mt2d2/servo,boghison/servo,CJ8664/servo,kindersung/servo,mbrubeck/servo,mattnenterprise/servo,aweinstock314/servo,mt2d2/servo,runarberg/servo,larsbergstrom/servo,jlegendary/servo,sadmansk/servo,jimberlage/servo,brendandahl/servo,tempbottle/servo,cbrewster/servo,pyfisch/servo,SimonSapin/servo,nnethercote/servo,wartman4404/servo,codemac/servo,WriterOfAlicrow/servo,caldwell/servo,codemac/servo,paulrouget/servo,jdramani/servo,eddyb/servo,brendandahl/servo,wartman4404/servo,tafia/servo,s142857/servo,youprofit/servo,deokjinkim/servo,AnthonyBroadCrawford/servo,youprofit/servo,nerith/servo,tafia/servo,mt2d2/servo,CJ8664/servo,dagnir/servo,mbrubeck/servo,pyecs/servo,tschneidereit/servo,huonw/servo,larsbergstrom/servo,KiChjang/servo,DominoTree/servo,DominoTree/servo,sadmansk/servo,nick-thompson/servo,wartman4404/servo,szeged/servo,DominoTree/servo,avadacatavra/servo,cbrewster/servo,bjwbell/servo,zentner-kyle/servo,avadacatavra/servo,dsandeephegde/servo,rixrix/servo,nerith/servo,GreenRecycleBin/servo,mt2d2/servo,aidanhs/servo,vks/servo,larsbergstrom/servo,AnthonyBroadCrawford/servo,mattnenterprise/servo,pgonda/servo,dati91/servo,dati91/servo,wartman4404/servo,runarberg/servo,KiChjang/servo,j3parker/servo,huonw/servo,ConnorGBrewster/servo,jimberlage/servo,akosel/servo,KiChjang/servo,bjwbell/servo,splav/servo,emilio/servo,zentner-kyle/servo,mattnenterprise/servo,mdibaiee/servo,nnethercote/servo,aidanhs/servo,ryancanhelpyou/servo,sadmansk/servo,GyrosOfWar/servo,GyrosOfWar/servo,walac/servo,larsbergstrom/servo,KiChjang/servo,dhananjay92/servo,zentner-kyle/servo,mattnenterprise/servo,pyfisch/servo,mbrubeck/servo,sadmansk/servo,bjwbell/servo,mdibaiee/servo,youprofit/servo,jgraham/servo,meh/servo,fiji-flo/servo,youprofit/servo,pyecs/servo,walac/servo,fiji-flo/servo,dati91/servo,meh/servo,ConnorGBrewster/servo,dvberkel/servo,dsandeephegde/servo,ryancanhelpyou/servo,zhangjunlei26/servo,boghison/servo,pyfisch/servo,saneyuki/servo,aweinstock314/servo,pyfisch/servo,nick-thompson/servo,zentner-kyle/servo,KiChjang/servo,codemac/servo,jlegendary/servo,dhananjay92/servo,pyecs/servo,dagnir/servo,j3parker/servo,RenaudParis/servo,mattnenterprise/servo,brendandahl/servo,wartman4404/servo,jimberlage/servo,A-deLuna/servo,saratang/servo,peterjoel/servo,emilio/servo,aweinstock314/servo,samfoo/servo,caldwell/servo,codemac/servo,zhangjunlei26/servo,fiji-flo/servo,A-deLuna/servo,dagnir/servo,nnethercote/servo,nrc/servo,walac/servo,notriddle/servo,thiagopnts/servo,ryancanhelpyou/servo,pgonda/servo,notriddle/servo,g-k/servo,saratang/servo,dati91/servo,RenaudParis/servo,upsuper/servo,szeged/servo,g-k/servo,boghison/servo,rentongzhang/servo,saneyuki/servo,DominoTree/servo,AnthonyBroadCrawford/servo,meh/servo,fiji-flo/servo,GyrosOfWar/servo,g-k/servo,g-k/servo,kindersung/servo,dhananjay92/servo,anthgur/servo,WriterOfAlicrow/servo,jdramani/servo,mattnenterprise/servo,dvberkel/servo,saratang/servo,pyecs/servo,dvberkel/servo,jlegendary/servo,A-deLuna/servo,anthgur/servo,hyowon/servo,pyecs/servo,tempbottle/servo,zentner-kyle/servo,pgonda/servo,dhananjay92/servo,boghison/servo,mattnenterprise/servo,ConnorGBrewster/servo,jgraham/servo,GreenRecycleBin/servo,splav/servo,aweinstock314/servo,tempbottle/servo,runarberg/servo,KiChjang/servo,samfoo/servo,pyecs/servo,nrc/servo,CJ8664/servo,tafia/servo,rixrix/servo,eddyb/servo,steveklabnik/servo,mbrubeck/servo,thiagopnts/servo,thiagopnts/servo,fiji-flo/servo,nerith/servo,DominoTree/servo,hyowon/servo,paulrouget/servo,jgraham/servo,tempbottle/servo,peterjoel/servo,A-deLuna/servo,zhangjunlei26/servo,RenaudParis/servo,avadacatavra/servo,dagnir/servo,emilio/servo,meh/servo,akosel/servo,ConnorGBrewster/servo,GreenRecycleBin/servo,akosel/servo,steveklabnik/servo,nrc/servo,RenaudParis/servo,mbrubeck/servo,GyrosOfWar/servo,emilio/servo,youprofit/servo,dhananjay92/servo,hyowon/servo,sadmansk/servo,splav/servo,nerith/servo,nnethercote/servo,canaltinova/servo,nnethercote/servo,tafia/servo,avadacatavra/servo,canaltinova/servo,paulrouget/servo,upsuper/servo,sadmansk/servo,jimberlage/servo,runarberg/servo,eddyb/servo,pyfisch/servo,walac/servo,caldwell/servo,peterjoel/servo,ryancanhelpyou/servo,jdramani/servo,RenaudParis/servo,notriddle/servo,tafia/servo,saratang/servo,GreenRecycleBin/servo,youprofit/servo,jimberlage/servo,jimberlage/servo,GyrosOfWar/servo,thiagopnts/servo,deokjinkim/servo,RenaudParis/servo,saneyuki/servo,rixrix/servo,kindersung/servo,aidanhs/servo,jgraham/servo,ryancanhelpyou/servo,s142857/servo,AnthonyBroadCrawford/servo,nrc/servo,samfoo/servo,GreenRecycleBin/servo,mbrubeck/servo,paulrouget/servo,pyecs/servo,zhangjunlei26/servo,karlito40/servo,RenaudParis/servo,huonw/servo,walac/servo,canaltinova/servo,peterjoel/servo,meh/servo,nerith/servo,cbrewster/servo,avadacatavra/servo,mt2d2/servo,nrc/servo,AnthonyBroadCrawford/servo