title: OCUnit (SenTestingKit) error file is not of required architecture
body: <p>I'm trying to build a project that uses OCUnit to run tests but get the following errors when linking:</p>
  
  <pre><code>ld: warning: in /Developer/SDKs/MacOSX10.5.sdk/Library/Frameworks//SenTestingKit.framework/SenTestingKit, file is not of required architecture
  Undefined symbols:
    "_STComposeString", referenced from:
        -[ReaderTest testEmptyFile] in ReaderTest.o
        -[ReaderTest testReadOneLine] in ReaderTest.o
        -[ReaderTest testReadOneLine] in ReaderTest.o
  
    "_OBJC_CLASS_$_SenTestCase", referenced from:
        _OBJC_CLASS_$_ReaderTest in ReaderTest.o
        _OBJC_CLASS_$_ActionUserInfoReaderTest in ActionUserInfoReaderTest.o
    "_OBJC_METACLASS_$_SenTestCase", referenced from:
        _OBJC_METACLASS_$_ReaderTest in ReaderTest.o
        _OBJC_METACLASS_$_ActionUserInfoReaderTest in ActionUserInfoReaderTest.o
  ld: symbol(s) not found
  collect2: ld returned 1 exit status
  </code></pre>
  
  <p>I was able to build and run with OCUnit without any problem before. This problem appeared this week but I can't tell as result of what change. I tried reinstalling XCode with the iPhone SDK 3.2.1 to no avail.</p>
  
  <p>If I do get info on /Library/Frameworks/SenTestingKit.framework/Versions/A/SenTestingKit, I get "Kind: Unix Executable File (PowerPC)". This tends to indicate why I'm having a problem since I'm building on an Intel platform for architecture x86_64. However, I don't understand how it could have worked before and stopped working...</p>
  
  <p>Thanks for your help.</p>