这两天由于同事都相继更新了系统和XCode10导致有些没更新系统和XCode的同事代码遇到一些问题，下面列出我遇见的几个问题：
问题一、Build input file cannot be found:'/Users/xxxxx/lib/DataLib/build/Debug-iphoneos/libDataLib.a'
报错图片如下：
xxx.a找不到.png
问题二、Multiple commands produce
问题详情
:-1: Multiple commands produce '/Users/mac/Library/Developer/Xcode/DerivedData/NewAirCloud-aleqredxbgkylvbkglvqefavfggd/Build/Products/Debug-iphoneos/NewAirCloud.app/Info.plist':
1) Target 'NewAirCloud' (project 'NewAirCloud') has copy command from '/Users/mac/Desktop/NewAirCloud-iOS/NewAirCloud/NewAirCloud/External/BaiDuAR/Vendors/SSZipArchive/Info.plist' to '/Users/mac/Library/Developer/Xcode/DerivedData/NewAirCloud-aleqredxbgkylvbkglvqefavfggd/Build/Products/Debug-iphoneos/NewAirCloud.app/Info.plist'
2) Target 'NewAirCloud' (project 'NewAirCloud') has process command with output '/Users/mac/Library/Developer/Xcode/DerivedData/NewAirCloud-aleqredxbgkylvbkglvqefavfggd/Build/Products/Debug-iphoneos/NewAirCloud.app/Info.plist'
问题截图如下：
Multiple commands.png
错误原因：
原因是XCode10更改默认的编译系统如下图：
projectSetting.png
问题一、二、解决办法：
1.点击File --> Project Setting --> Build System 选择Legacy Build System -->Done
2.command + shift +k：清理缓存即可编译成功
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2.png
问题三、ld: library not found for -lstdc++.6.0.9
问题截图：
libstdc++.6.0.9.png
问题原因：
Xcode 10 中移除了 “-libstdc++.6.0.9” 等一些过期很久的库
解决办法：
1.移除-libstdc++.6.0.9
TARGETS --> Build Phases -->Link Binary With Libraries 找到libstdc++.6.0.9选中点击➖图标移除
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2.需要在旧版Xcode 9 中查找到“-lstdc++.6.0.9”库之后，复制一份放入Xcode 10 lib库中。
具体操作连接:https://www.jianshu.com/p/3e29e9d897c8
问题四："OBJC_CLASS$_CNContactStore", referenced from:objc-class-ref in iflyMSC(IFlyContact.o)
"_OBJC_CLASS_$_CNContactStore", referenced from:
objc-class-ref in iflyMSC(IFlyContact.o)
"_OBJC_CLASS_$_CNContactFetchRequest", referenced from:
objc-class-ref in iflyMSC(IFlyContact.o)
"_CNContactGivenNameKey", referenced from:
-[IFlyContact fetchContactWithContactStore:] in iflyMSC(IFlyContact.o)
"_CNContactFamilyNameKey", referenced from:
-[IFlyContact fetchContactWithContactStore:] in iflyMSC(IFlyContact.o)
问题截图：
科大讯飞.png
问题原因：
科大讯飞sdk需要添加以下四个依赖库，升级Xcode10后莫名找不到这些依赖库
image.png
解决办法：
添加相应依赖：TARGETS --> Build Phases -->Link Binary With Libraries点击➕号,搜索相应framework，点击add
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