title: Undefined symbols for architecture x86_64: for Firebase in Xcode 8.3.2
body: <p>I installed firebase by manually to my Xcode for storage data purpose. I followed README from DOCS and integrated. But, the issue is, after everything setup, I am getting following compiler errors.</p>
  
  <pre><code>Undefined symbols for architecture x86_64:
    “_kFIRAppDiagnosticsErrorKey”, referenced from:
        +[FIRDiagnostics logDiagnostics:] in FirebaseCoreDiagnostics(FIRDiagnostics_0c03a82afb19aa444c2f4902b5217b60.o)
    “_kFIRAppDiagnosticsSDKNameKey”, referenced from:
        +[FIRDiagnostics logDiagnostics:] in FirebaseCoreDiagnostics(FIRDiagnostics_0c03a82afb19aa444c2f4902b5217b60.o)
    “_kFIRAppDiagnosticsSDKVersionKey”, referenced from:
        +[FIRDiagnostics logDiagnostics:] in FirebaseCoreDiagnostics(FIRDiagnostics_0c03a82afb19aa444c2f4902b5217b60.o)
    “_kFIRAppDiagnosticsFIRAppKey”, referenced from:
        +[FIRDiagnostics logDiagnostics:] in FirebaseCoreDiagnostics(FIRDiagnostics_0c03a82afb19aa444c2f4902b5217b60.o)
    “_kFIRServiceAuthUI”, referenced from:
        +[FIRDiagnostics populateLogProtoWithInstalledServices:] in FirebaseCoreDiagnostics(FIRDiagnostics_0c03a82afb19aa444c2f4902b5217b60.o)
        +[FIRDiagnostics mapFromServiceStringToTypeEnum:] in FirebaseCoreDiagnostics(FIRDiagnostics_0c03a82afb19aa444c2f4902b5217b60.o)
    “_kFIRAppDiagnosticsNotification”, referenced from:
        +[FIRDiagnostics load] in FirebaseCoreDiagnostics(FIRDiagnostics_0c03a82afb19aa444c2f4902b5217b60.o)
    “_FIRAuthStateDidChangeInternalNotificationAppKey”, referenced from:
        -[FAuthStateListenerWrapper authStateDidChangeNotification:] in FirebaseDatabase(FAuthTokenProvider_213581f9a756863b453764defdcb42ec.o)
    “_FIRAuthStateDidChangeInternalNotificationTokenKey”, referenced from:
        -[FAuthStateListenerWrapper authStateDidChangeNotification:] in FirebaseDatabase(FAuthTokenProvider_213581f9a756863b453764defdcb42ec.o)
    “_FIRAuthStateDidChangeInternalNotification”, referenced from:
        -[FAuthStateListenerWrapper initWithListener:app:] in FirebaseDatabase(FAuthTokenProvider_213581f9a756863b453764defdcb42ec.o)
    “_kFIRAppDiagnosticsConfigurationTypeKey”, referenced from:
        +[FIRDiagnostics logDiagnostics:] in FirebaseCoreDiagnostics(FIRDiagnostics_0c03a82afb19aa444c2f4902b5217b60.o)
    “_utf8_nextCharSafeBody”, referenced from:
        -[FSRWebSocket _innerPumpScanner] in FirebaseDatabase(FSRWebSocket_221b45e2259898169b2d29adbe0c7833.o)
  ld: symbol(s) not found for architecture x86_64
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  </code></pre>