Command /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/lex f

错误的原因:

Command /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/lex failed with exit code 1

ProcessPCH++ "/Users/xxxx/Library/Developer/Xcode/DerivedData/English_Reader-alybxowggrudboejoylghzohavko/Build/Intermediates/PrecompiledHeaders/English Reader-Prefix-fldqdedtnerfrubpymgklsjvzccz/English Reader-Prefix.pch.pth" "English Reader/English Reader-Prefix.pch"
normal i386 objective-c++ com.apple.compilers.llvm.clang.1_0.compiler

clang: error: invalid deployment target for -stdlib=libc++ (requires iOS 5.0 or later)

Command /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang failed with exit code 1

解决方法：

将Apple LLVM compiler 4.1 - Language ->c++ Standard Library 修改为 libstdc++ （GNU C++ standard library）