收到iOS12.0更新推送，網上各種說更新之后手機流暢度能提升70%，那個心里激動的呀，對于iOS開發(fā)者來說，更新手機必然需要更新Xcode，要不真機都不讓運行，Xcode從9.4.1更新到10.0之后開始報編譯錯誤，下面來說說如何解決。

報錯1：

:-1: Multiple commands produce '/Users/Simon/Library/Developer/Xcode/DerivedData/YueMeTV-emcpejoowcofgfdbrhckdzciyxgk/Build/Products/Debug-iphoneos/YueMeTV.app/Info.plist':
1) Target 'YueMeTV' (project 'YueMeTV') has copy command from '/Users/Simon/Desktop/公信/SmartHome_UIUE_New/Src/YueMeTV/yueme_cloud/Info.plist' to '/Users/Simon/Library/Developer/Xcode/DerivedData/YueMeTV-emcpejoowcofgfdbrhckdzciyxgk/Build/Products/Debug-iphoneos/YueMeTV.app/Info.plist'
2) Target 'YueMeTV' (project 'YueMeTV') has process command with output '/Users/Simon/Library/Developer/Xcode/DerivedData/YueMeTV-emcpejoowcofgfdbrhckdzciyxgk/Build/Products/Debug-iphoneos/YueMeTV.app/Info.plist'

解決鏈接：Xcode 10 Error: Multiple commands produce

文中的步驟是 Xcode->File->Project Settings-> Build System -> Legacy Build System.
1、In Xcode, go to File->Project/Workspace settings
2、Change the build system to Legacy Build system

報錯2：

ld: warning: directory not found for option '-F/Users/Simon/Desktop/公信/SmartHome_UIUE_New/Src/YueMeTV/tools/TYLoginSDK'
ld: library not found for -lstdc++.6.0.9
clang: error: linker command failed with exit code 1 (use -v to see invocation)

解決完上述再編譯報缺少lstdc++.6.0.9庫，在新xcode中發(fā)現(xiàn)已經去掉libstdc++.6.0.9，這就意味著項目中如果有第三方或者自己使用到lstdc++.6.0.9的地方都會報編譯錯誤。

臨時解決方案

1、 找到Xcode10之前的版本，搜索下面路勁找到libstdc++.6.0.9，
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/usr/lib
2、拷貝libstdc++.6.0.9到Xcode10.0對應路徑下，再編譯就不會報錯了。

參考鏈接：
Xcode 10 (iOS 12) does not contain libstdc++6.0.9
關于Xcode 10.0編譯不通過的問題 stdc++.6.0.9