编译时出现Xcode错误：ld：找不到架构x86_64 clang的符号

Question

我正在开发一个在编译项目时没有问题的iOS应用程序。但是现在，当我尝试编译时，我收到以下错误消息：

Undefined symbols for architecture x86_64:
  "_OBJC_CLASS_$_CKCalendarView", referenced from:
      objc-class-ref in CITSearchCarViewController.o
      objc-class-ref in CITAddNewDestViewController.o
      objc-class-ref in CITSearchViewController.o
      objc-class-ref in CITNewFlightAlertViewController.o
  "_OBJC_CLASS_$_HMSegmentedControl", referenced from:
      _OBJC_CLASS_$_CITSegmentedControl in CITSegmentedControl.o
  "_OBJC_CLASS_$_IBCoreDataStore", referenced from:
      objc-class-ref in CITSearchHistory.o
      objc-class-ref in CITJourneyData.o
      objc-class-ref in CITAlertManager.o
  "_OBJC_CLASS_$_MKNetworkEngine", referenced from:
      _OBJC_CLASS_$_CITNetworkEngine in CITNetworkEngine.o
  "_OBJC_CLASS_$_SSZipArchive", referenced from:
      objc-class-ref in CITUtils.o
  "_OBJC_CLASS_$_SVProgressHUD", referenced from:
      objc-class-ref in CITInitialViewController.o
      objc-class-ref in CITFlightAlertViewController.o
      objc-class-ref in CITSearchViewController.o
      objc-class-ref in CITSearchResultsViewController.o
      objc-class-ref in CITMultiDestViewController.o
      objc-class-ref in CITConfigurationViewController.o
      objc-class-ref in CITFlightDetailViewController.o
      ...
  "_OBJC_CLASS_$_TRAutocompleteView", referenced from:
      objc-class-ref in CITAddNewDestViewController.o
      objc-class-ref in CITSearchViewController.o
      objc-class-ref in CITNewFlightAlertViewController.o
  "_OBJC_METACLASS_$_HMSegmentedControl", referenced from:
      _OBJC_METACLASS_$_CITSegmentedControl in CITSegmentedControl.o
  "_OBJC_METACLASS_$_MKNetworkEngine", referenced from:
      _OBJC_METACLASS_$_CITNetworkEngine in CITNetworkEngine.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

我试图将架构i386更改为x86_64，但我得到了相同的结果。 最初问题是由于Xcode没有找到lpods库引起的。然后我试着＆＃34;清洁＆amp;建立＆＃34;到项目，但这可以工作。

我该怎么办？