最近在最新的Xcode11.5中编译从Github上下载的老项目，出现一个bug，提示如下：
Multiple commands produce '/xxx.app':
1) Target 'xxx' has create directory command with output '/Users/xxx/Library/Developer/Xcode/DerivedData/xxx-cbvukcttkoparwddqctpdtspmcov/Build/Products/Debug-iphonesimulator/xxx.app'
2) That command depends on command in Target 'xxx': script phase “[CP] Copy Pods Resources”
出现该问题是因为自Xcode10之后默认使用的build system是New build system，我们只要将build system设置成legacy build system就好了。
操作如下图：
