duplicate symbols in AdMob

If you're using the Admob v6.2 library make sure you're NOT using the -all_load linker flag, use the -ObjC linker flag instead.

If you can't find any "-all_load" params but also show this error.

you must goto the "project.xcodeproj" and replace "-all_load" with "-ObjC" in "project.pbxproj"