Add a fix for LLVM for late versions of clang

Change-Id: Id32b0b975af8bdff31c822cf5a67792fe7f785b1
Reviewed-on: https://swiftshader-review.googlesource.com/3301
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Greg Hartman <ghartman@google.com>