前陣子在更新cocoapods (gem update cocoapods)時發生了些error，如下： /Users/hothero/.rvm/rubies/ruby-1.9.2-p290/bin/ruby extconf.rb checking for -std=c99 option to compiler... *** extconf.rb failed *** Could not create Makefile due to some reason, probably lack of necessary libraries and/or headers. Check