问题
Ld /Users/guxinchao1/Desktop/three20/Build/Products/Debug-iphonesimulator/CoreUnitTests.octest/CoreUnitTests normal i386
cd /Users/guxinchao1/Desktop/three20/src/Three20Core
export IPHONEOS_DEPLOYMENT_TARGET=3.0
export PATH="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch i386 -bundle -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.1.sdk -L/Users/guxinchao1/Desktop/three20/Build/Products/Debug-iphonesimulator -L/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.1.sdk/usr/lib -F/Users/guxinchao1/Desktop/three20/Build/Products/Debug-iphonesimulator -F/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.1.sdk/Developer/Library/Frameworks -filelist /Users/guxinchao1/Desktop/three20/Build/Three20Core.build/Debug-iphonesimulator/Three20CoreUnitTests.build/Objects-normal/i386/CoreUnitTests.LinkFileList -Xlinker -objc_abi_version -Xlinker 2 -ObjC -framework UIKit -framework CoreGraphics -framework Foundation -framework SenTestingKit -framework CoreGraphics -fobjc-link-runtime -Xlinker -no_implicit_dylibs -mios-simulator-version-min=3.0 -lThree20Core -Xlinker -dependency_info -Xlinker /Users/guxinchao1/Desktop/three20/Build/Three20Core.build/Debug-iphonesimulator/Three20CoreUnitTests.build/Objects-normal/i386/CoreUnitTests_dependency_info.dat -o /Users/guxinchao1/Desktop/three20/Build/Products/Debug-iphonesimulator/CoreUnitTests.octest/CoreUnitTests
ld: symbol dyld_stub_binding_helper not found, normally in crt1.o/dylib1.o/bundle1.o for architecture i386 clang: error: linker command failed with exit code 1 (use -v to see invocation)
来源：https://stackoverflow.com/questions/28043720/three20the-three20-framework-of-the-source-code-error