Clang 5 and Clang 6 can no longer parse newer versions of libc++. As we can't specify the specific libc++ version in the decorator, let's only allow Clang versions that can parse all currently available libc++ versions.
Clang 5 and Clang 6 can no longer parse newer versions of libc++. As we can't specify the specific libc++ version in the decorator, let's only allow Clang versions that can parse all currently available libc++ versions.