This occurs when a header file is moved or deleted. The dependency
files contain the old header file and produce this error. The only way
I have found to get around this is to delete all *.d files when header
files are moved or deleted:
% cd LLVM_OBJ_DIR
% /bin/rm `find . -name '*.d'`
If someone knows a better way around this,I'd love to hear it too.