error: Multiple commands produce '/Users/omochi/work/swift-source/build/Xcode-ReleaseAssert+swift-DebugAssert/llvm-macosx-x86_64/include/llvm/Support': 1) CreateBuildDirectory /Users/omochi/work/swift-source/build/Xcode-ReleaseAssert+swift-DebugAssert/llvm-macosx-x86_64/include/llvm/Support 2) That command depends on command in Target 'llvm_vcsrevision_h' (project 'LLVM'): script phase “Generate include/llvm/Support” warning: duplicate output file '/Users/omochi/work/swift-source/build/Xcode-ReleaseAssert+swift-DebugAssert/llvm-macosx-x86_64/include/llvm/Support' on task: PhaseScriptExecution Generate include/llvm/Support /Users/omochi/work/swift-source/build/Xcode-ReleaseAssert+swift-DebugAssert/llvm-macosx-x86_64/include/llvm/Support/LLVM.build/Release/llvm_vcsrevision_h.build/Script-7FD889A2C0CC1336ED00F240.sh (in target 'llvm_vcsrevision_h' from project 'LLVM') ** BUILD FAILED **