Showing All Errors Only
Ld /Users/zhanghairui/Library/Developer/Xcode/DerivedData/KnowledgeService-ewnxzxvqbpgosbbmupfmjqbkonez/Build/Products/Debug-iphonesimulator/KnowledgeService.app/KnowledgeService normal x86_64
cd /Users/zhanghairui/Desktop/KnowledgeService
export IPHONEOS_DEPLOYMENT_TARGET=8.0
export PATH="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator11.1.sdk -L/Users/zhanghairui/Library/Developer/Xcode/DerivedData/KnowledgeService-
解决方式如下：
先退出xcode，再把/Users/appleapple/Library/Developer/Xcode/DerivedData/下面的东西都删除（DerivedData本身不要删），再启动xcode，再rebuild.
