在XCode中使用-Objc标志给出Mach-O链接器错误

我正在尝试将Google AdMob集成到我的iOS应用中，但为了使用他们的SDK，我需要使用-ObjC链接器标志来加载它们的类别方法。 没有链接器，一切正常，但是当我在Debug和Release下的Xcode中添加-ObjC标志时，我得到了一个Mach-O链接器错误的巨大列表（如下）。

我使用Box2D，它使用C和C ++，所以起初我以为我只需要包含适当的链接器标志，但我找不到一个修复错误。

我也尝试导入libstdc ++。dylib库，它摆脱了原始的链接器错误，而是用声明我在CCScrollLayer中有大量重复符号的错误replace它们。

我不知所措 任何帮助都将非常非常感激。

-Objc错误：

Undefined symbols for architecture i386: "std::string::c_str() const", referenced from: TiXmlElement* createValueElm<int>(char const*, int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<float>(char const*, float) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<long long>(char const*, long long) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<unsigned long>(char const*, unsigned long) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<unsigned int>(char const*, unsigned int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) void setAttribute<char const*>(TiXmlElement*, char const*, char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) void setAttribute<int>(TiXmlElement*, char const*, int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) ... "std::basic_ostringstream<char, std::char_traits<char>, std::allocator<char> >::str() const", referenced from: TiXmlElement* createValueElm<int>(char const*, int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<float>(char const*, float) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<long long>(char const*, long long) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<unsigned long>(char const*, unsigned long) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<unsigned int>(char const*, unsigned int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) void setAttribute<char const*>(TiXmlElement*, char const*, char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) void setAttribute<int>(TiXmlElement*, char const*, int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) ... "std::allocator<char>::allocator()", referenced from: float stringToValue<float>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) int stringToValue<int>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) unsigned int stringToValue<unsigned int>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) unsigned long stringToValue<unsigned long>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) long long stringToValue<long long>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::allocator<char>::~allocator()", referenced from: float stringToValue<float>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) int stringToValue<int>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) unsigned int stringToValue<unsigned int>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) unsigned long stringToValue<unsigned long>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) long long stringToValue<long long>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::istream::operator>>(float&)", referenced from: float stringToValue<float>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::istream::operator>>(int&)", referenced from: int stringToValue<int>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::istream::operator>>(unsigned int&)", referenced from: unsigned int stringToValue<unsigned int>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::istream::operator>>(unsigned long&)", referenced from: unsigned long stringToValue<unsigned long>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::istream::operator>>(long long&)", referenced from: long long stringToValue<long long>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::ostream::operator<<(float)", referenced from: TiXmlElement* createValueElm<float>(char const*, float) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) void setAttribute<float>(TiXmlElement*, char const*, float) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::ostream::operator<<(int)", referenced from: TiXmlElement* createValueElm<int>(char const*, int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) void setAttribute<int>(TiXmlElement*, char const*, int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::ostream::operator<<(unsigned int)", referenced from: TiXmlElement* createValueElm<unsigned int>(char const*, unsigned int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::ostream::operator<<(unsigned long)", referenced from: TiXmlElement* createValueElm<unsigned long>(char const*, unsigned long) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::ostream::operator<<(long long)", referenced from: TiXmlElement* createValueElm<long long>(char const*, long long) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&)", referenced from: float stringToValue<float>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) int stringToValue<int>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) unsigned int stringToValue<unsigned int>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) unsigned long stringToValue<unsigned long>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) long long stringToValue<long long>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()", referenced from: TiXmlElement* createValueElm<int>(char const*, int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<float>(char const*, float) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<long long>(char const*, long long) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<unsigned long>(char const*, unsigned long) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<unsigned int>(char const*, unsigned int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) void setAttribute<char const*>(TiXmlElement*, char const*, char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) void setAttribute<int>(TiXmlElement*, char const*, int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) ... "std::basic_istringstream<char, std::char_traits<char>, std::allocator<char> >::basic_istringstream(std::string const&, std::_Ios_Openmode)", referenced from: float stringToValue<float>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) int stringToValue<int>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) unsigned int stringToValue<unsigned int>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) unsigned long stringToValue<unsigned long>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) long long stringToValue<long long>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::basic_istringstream<char, std::char_traits<char>, std::allocator<char> >::~basic_istringstream()", referenced from: float stringToValue<float>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) int stringToValue<int>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) unsigned int stringToValue<unsigned int>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) unsigned long stringToValue<unsigned long>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) long long stringToValue<long long>(char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::basic_ostringstream<char, std::char_traits<char>, std::allocator<char> >::basic_ostringstream(std::_Ios_Openmode)", referenced from: TiXmlElement* createValueElm<int>(char const*, int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<float>(char const*, float) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<long long>(char const*, long long) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<unsigned long>(char const*, unsigned long) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<unsigned int>(char const*, unsigned int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) void setAttribute<char const*>(TiXmlElement*, char const*, char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) void setAttribute<int>(TiXmlElement*, char const*, int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) ... "std::basic_ostringstream<char, std::char_traits<char>, std::allocator<char> >::~basic_ostringstream()", referenced from: TiXmlElement* createValueElm<int>(char const*, int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<float>(char const*, float) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<long long>(char const*, long long) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<unsigned long>(char const*, unsigned long) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) TiXmlElement* createValueElm<unsigned int>(char const*, unsigned int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) void setAttribute<char const*>(TiXmlElement*, char const*, char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) void setAttribute<int>(TiXmlElement*, char const*, int) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) ... "std::_Rb_tree_decrement(std::_Rb_tree_node_base*)", referenced from: std::_Rb_tree_iterator<std::pair<long long const, cpShape*> >::operator--() in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) std::_Rb_tree_iterator<std::pair<long long const, cpBody*> >::operator--() in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::_Rb_tree_increment(std::_Rb_tree_node_base*)", referenced from: std::_Rb_tree_iterator<std::pair<long long const, cpShape*> >::operator++() in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) std::_Rb_tree_iterator<std::pair<long long const, cpBody*> >::operator++() in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::_Rb_tree_insert_and_rebalance(bool, std::_Rb_tree_node_base*, std::_Rb_tree_node_base*, std::_Rb_tree_node_base&)", referenced from: std::_Rb_tree<long long, std::pair<long long const, cpShape*>, std::_Select1st<std::pair<long long const, cpShape*> >, std::less<long long>, std::allocator<std::pair<long long const, cpShape*> > >::_M_insert(std::_Rb_tree_node_base*, std::_Rb_tree_node_base*, std::pair<long long const, cpShape*> const&) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) std::_Rb_tree<long long, std::pair<long long const, cpBody*>, std::_Select1st<std::pair<long long const, cpBody*> >, std::less<long long>, std::allocator<std::pair<long long const, cpBody*> > >::_M_insert(std::_Rb_tree_node_base*, std::_Rb_tree_node_base*, std::pair<long long const, cpBody*> const&) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) "std::basic_ostream<char, std::char_traits<char> >& std::operator<<<std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)", referenced from: void setAttribute<char const*>(TiXmlElement*, char const*, char const*) in libchipmunk-spacemanager-ios.a(cpSpaceSerializer.o) ld: symbol(s) not found for architecture i386 clang: error: linker command failed with exit code 1 (use -v to see invocation) 

libstdc ++。dylib的错误：

 duplicate symbol _OBJC_IVAR_$_CCScrollLayer.layers_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.currentScreen_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.pagesIndicatorNormalColor_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.pagesIndicatorSelectedColor_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.prevScreen_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.scrollTouch_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.startSwipe_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.state_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.marginOffset_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.delegate_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.minimumTouchLengthToSlide_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.minimumTouchLengthToChangePage_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.showPagesIndicator_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.pagesIndicatorPosition_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.pagesWidthOffset_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_IVAR_$_CCScrollLayer.stealTouches_ in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_CLASS_$_CCScrollLayer in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) duplicate symbol _OBJC_METACLASS_$_CCScrollLayer in: /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Intermediates/ballBounce.build/Debug-iphonesimulator/ballBounce-iOS.build/Objects-normal/i386/CCScrollLayer.o /Users/Stevenpd/Library/Developer/Xcode/DerivedData/Kobold2D-bhlexwnjvtnneigernvsargfadgb/Build/Products/Debug-iphonesimulator/libcocos2d-extensions-ios.a(CCScrollLayer.o) ld: 18 duplicate symbols for architecture i386 clang: error: linker command failed with exit code 1 (use -v to see invocation)