Undefined symbols for architecture x86_64:
  "_ACAccountTypeIdentifierTwitter", referenced from:
      -[PF_Twitter getLocalTwitterAccountAsync] in Parse(PF_Twitter.o)
  "_OBJC_CLASS_$_ACAccountStore", referenced from:
      objc-class-ref in Parse(PF_Twitter.o)
  "_OBJC_CLASS_$_SLComposeViewController", referenced from:
      objc-class-ref in Parse(PF_Twitter.o)
  "_OBJC_CLASS_$_SLRequest", referenced from:
      objc-class-ref in Parse(PF_Twitter.o)
  "_SLServiceTypeTwitter", referenced from:
      -[PF_Twitter getAccessTokenForReverseAuthAsync:localTwitterAccount:] in Parse(PF_Twitter.o)
      -[PF_Twitter getLocalTwitterAccountAsync] in Parse(PF_Twitter.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Under Targets, General, Linked Frameworks and Libraries add:

• Social.framework
• Accounts.framework