iOS development-"Duplicate symbol for architecture i386" workaround

Today, when we integrated the project, I encountered such a problem.

Duplicate symbol _flag in:
/users/apple/library/developer/xcode/deriveddata/bluetoothphone-fspknidhnizzjygmuqngfcklvnic/build/ intermediates/bluetoothphone.build/debug-iphonesimulator/bluetoothphone.build/objects-normal/i386/dialvc.o
/users/apple/library/developer/xcode/deriveddata/bluetoothphone-fspknidhnizzjygmuqngfcklvnic/build/ intermediates/bluetoothphone.build/debug-iphonesimulator/bluetoothphone.build/objects-normal/i386/ Personallist.o
Ld:1 duplicate symbol for architecture i386
Clang:error:linker command failed with exit code 1 (use-v to see invocation)

Analysis,.

As you can see, the error type is duplicate (duplicate) error identification is _flag error location in DIALVC and Personallist

So, search, flag. Found...

All right. Just get rid of one of them.