While trying to add admob to cocos2d, I get this error:
ld: duplicate symbol .objc_category_name_NSCharacterSet_NSCharacterSet_Extensions in /Users/Home/Documents/Xcode/Rocket Boy 2/AdMob/libAdMobDeviceNoThumb.a(NSCharacterSet_Extensions.o) and /Users/Home/Documents/Xcode/Rocket Boy 2/build/Distribution-iphoneos/libcocos2d libraries.a(NSCharacterSet_Extensions.o)
I searched and it never seemed to have happened to anyone else.
Anyone know what I should do ?