devel/libcutl: unbreak with libc++ 8

In file included from exception.cxx:5:
In file included from /usr/include/c++/v1/typeinfo:61:
In file included from /usr/include/c++/v1/exception:81:
In file included from /usr/include/c++/v1/cstddef:38:
../version:1:1: error: expected unqualified-id
1.10.0
^

PR: 236192
Approved by: portmgr blanket