title: Darn linker errors XCode 4.3--algorithm to solve them?
body: <blockquote>
    <p>Undefined symbols for architecture i386:<br>
    "_OBJC_CLASS_$_AppDelegate_Shared", referenced from:
          _OBJC_CLASS_$_AppDelegate_iPad in AppDelegate_iPad.o
           "_OBJC_METACLASS_$_AppDelegate_Shared", referenced from:
          _OBJC_METACLASS_$_AppDelegate_iPad in AppDelegate_iPad.o ld: symbol(s) not found for architecture i386 clang: error: linker command
    failed with exit code 1 (use -v to see invocation)</p>
  </blockquote>
  
  <p>Hello, this is a straight up AppDelegate, and I'm getting this error. Any ideas? There's no library to link to or anything.  I've seen these errors time and time again in XCode, but the causes have ranged from a libxml2 library being not right (needed libxml2.7.3), to just something odd in XCode itself.  No idea what to do next, but obviously would like the program to compile.  Thanks!</p>