pp-trace error when doing a test scan

I built and installed pp-trace from the extra clang tools, running the tool against some of clangs own header files I get #include errors, here’s a sample output.

./pp-trace /usr/local/llvm40/include/clang/Sema/AttributeList.h
In file included from /usr/local/llvm40/include/clang/Sema/AttributeList.h:18:
In file included from /usr/local/llvm40/include/clang/Basic/SourceLocation.h:18:
In file included from /usr/local/llvm40/include/clang/Basic/LLVM.h:22:
In file included from /usr/local/llvm40/include/llvm/Support/Casting.h:19:
/usr/local/llvm40/include/llvm/Support/type_traits.h:17:10: fatal error: ‘type_traits’ file not found
#include <type_traits>
^~~~~~~~~~~~~
1 error generated.
Error while processing /usr/local/llvm40/include/clang/Sema/AttributeList.h.

Why would the <type_traits> not be found?

Best