我正在尝试在ruby1.8.7上安装johnson2.0.0pre3gem，但出现此编译错误:(stable)$geminstalljohnson-v'2.0.0pre3'Buildingnativeextensions.Thiscouldtakeawhile...ERROR:Errorinstallingjohnson:ERROR:Failedtobuildgemnativeextension./Users/aaa/.rvm/rubies/ruby-1.8.7-p374/bin/rubyextconf.rbcreatingcache./config.cachecheckingho
