fix build for ruby 1.8.7
fix build for ruby 1.8.7

chulkilee/bundler,mattbrictson/bundler-1,CorainChicago/bundler,1337807/bundler,philnash/bundler,cdwort/bundler,asutoshpalai/bundler,rkh/bundler,Teino1978-Corp/Teino1978-Corp-bundler,bundler/bundler,Eric-Guo/bundler,wenderjean/bundler,AiyionPrime/bundler,ligi/bundler,mvz/bundler,jasonkarns/bundler,cstrahan/bundler,jingweno/bundler,haonaturel/bundler,robinboening/bundler,eagletmt/bundler,steved/bundler,jingweno/bundler,zhangkuaiji/bundler,davydovanton/bundler,h4ck3rm1k3/bundler,asymmetric/bundler,dilumnavanjana/bundler,dilumnavanjana/bundler,smlance/bundler,TimMoore/bundler,lmtim/bundler,gregkare/bundler,gentoo/bundler,neslom/bundler,smlance/bundler,mattbrictson/bundler-1,ximus/bundler,jaym/bundler,EasonYi/bundler,agis-/bundler,JuanitoFatas/bundler,simplybusiness/bundler,carpodaster/bundler,cstrahan/bundler,christer155/bundler,vemmaverve/bundler,asutoshpalai/bundler,e2/bundler,mpapis/bundler,jasonkarns/bundler,AiyionPrime/bundler,nju520/bundler,tgxworld/bundler,anil826/bundler,kohgpat/bundler,lmtim/bundler,ipmobiletech/bundler,roseweixel/bundler,zhangkuaiji/bundler,pjump/bundler,carpodaster/bundler,pivotal-cf-experimental/bundler,ngpestelos/bundler,mpapis/bundler,nju520/bundler,Eric-Guo/bundler,chef/bundler,Elffers/bundler,bronzdoc/bundler,joshsoftware/bundler,bronzdoc/bundler,Teino1978-Corp/Teino1978-Corp-bundler,EthanK28/bundler,steved/bundler,neslom/bundler,ligi/bundler,schaary/bundler,CorainChicago/bundler,EasonYi/bundler,suhastech/bundler,bundler/bundler,PG-kura/bundler,seanlinsley/bundler,ipmobiletech/bundler,chulkilee/bundler,byroot/bundler,sideci-sample/sideci-sample-bundler,elovelan/bundler,frsyuki/bundler,danimashu/bundler,asymmetric/bundler,RochesterinNYC/bundler,christer155/bundler,mvz/bundler,RochesterinNYC/bundler,pivotal-cf-experimental/bundler,simplybusiness/bundler,Wirachmat/bundler,gregkare/bundler,Wirachmat/bundler,elovelan/bundler,r7kamura/bundler,byroot/bundler,ngpestelos/bundler,ximus/bundler,masarakki/bundler,sideci-sample/sideci-sample-bundler,cdwort/bundler,wenderjean/bundler,seanlinsley/bundler,davydovanton/bundler,philnash/bundler,schaary/bundler,Elffers/bundler,roseweixel/bundler,patvice/bundler,anil826/bundler,joshsoftware/bundler,haonature/bundler,agis-/bundler,masarakki/bundler,patvice/bundler,jaym/bundler,mdorrance/bundler,danimashu/bundler,haonature888/bundler,twcctz500000/bundler,suhastech/bundler,tgxworld/bundler,robinboening/bundler,mdorrance/bundler,haocafes/bundler,kohgpat/bundler,frsyuki/bundler,h4ck3rm1k3/bundler,TimMoore/bundler,EthanK28/bundler,PG-kura/bundler,chef/bundler,pjump/bundler