title: Getting "apple mach-o linker id error undefined symbols for architecture i386" when implement a Library in iOS5
body: <p>I'm having troubles to implement the PayPal Library in XCode 4.
  I get this error when I try to build the project:</p>
  
  <blockquote>
    <p>Undefined symbols for architecture i386:<br>
      "_xmlParseMemory", referenced from:<br>
          -[AdaptivePaymentsSOAP11Binding_CancelPreapproval connectionDidFinishLoading:] in libPayPalMPL.a(AdaptivePayments.o)<br>
          -[AdaptivePaymentsSOAP11Binding_ConfirmPreapproval connectionDidFinishLoading:] in libPayPalMPL.a(AdaptivePayments.o)<br>
          -[AdaptivePaymentsSOAP11Binding_ConvertCurrency connectionDidFinishLoading:] in libPayPalMPL.a(AdaptivePayments.o)<br>
          -[AdaptivePaymentsSOAP11Binding_ExecutePayment connectionDidFinishLoading:] in libPayPalMPL.a(AdaptivePayments.o)<br>
          -[AdaptivePaymentsSOAP11Binding_GetPaymentOptions connectionDidFinishLoading:] in libPayPalMPL.a(AdaptivePayments.o)<br>
          -[AdaptivePaymentsSOAP11Binding_PaymentDetails connectionDidFinishLoading:] in libPayPalMPL.a(AdaptivePayments.o)<br>
          -[AdaptivePaymentsSOAP11Binding_Pay connectionDidFinishLoading:] in libPayPalMPL.a(AdaptivePayments.o)<br>
          ...</p>
  </blockquote>
  
  <p>Searching on the web I found that this is a tipical error when passing from XC3 to XC4. Maybe the Library isn't updated. But that file .a that you see there seems to be uneditable.</p>