今天到了新公司，装了xcode4.0.2，随便建了一个工程，总会有十多个错误导致编译失败：
错误如下：
error: unable to create '/Users/［用户名］/Library/Developer/Xcode/DerivedData/gfhfgh-edhpobgjmxjmsmgimuzpzwmrvgaq/Build/Intermediates' (Permission denied)
…
Unable to create directory /Users/moqi/Library/Developer/Xcode/DerivedData/gfhfgh-edhpobgjmxjmsmgimuzpzwmrvgaq/Build/Intermediates/gfhfgh.build/Debug-iphonesimulator/gfhfgh.build/Objects-normal/i386
…
The file “Info.plist” doesn’t exist.
大致如上，
解决方法：打开终端输入：sudo chmod -R 777 /Users/[your user directory]/Library/Developer/
For some reason, when installing Cocos2d, it also modified the file
permission? Anyway, did not look into that since it is working now.
原文地址：http://www.iphonewarroom.com/2011/07/how-to-fix-warning-couldnt-add.html
