Occasionally the build of LLVMLibDriver will fail because Attributes.inc has not been generated yet. Add an explicit dependency, so that we can guarantee that the file has been generated before LLVMLibDriver is build.
[error]llvm\include\llvm\IR\Attributes.h(73,0): Error C1083: Cannot open include file: 'llvm/IR/Attributes.inc': No such file or directory
llvm\include\llvm/IR/Attributes.h(73): fatal error C1083: Cannot open include file: 'llvm/IR/Attributes.inc': No such file or directory [LLVMLibDriver.vcxproj]