Enforce linking with a shared library with -Wl,--as-needed (when only templates are provided)

I am creating a template-only C++ library. However, I'd like to provide an 'empty' shared library as well, so that through controlling SONAME I would be able to enforce rebuilds of the template consumers whenever the templates change in a way resulting in instantiated template ABI incompatibility.

Sadly, if a particular user has -Wl,--as-needed in his LDFLAGS, the linker is going to remove my shared library from NEEDED because the compiled executable is not requesting any symbols from it. How can I ensure that the program will always be linked against my library, preferably not introducing unnecessary dummy function calls (or if I have to, making them least burdening)?

Edit: as a note, the particular template class provides static methods, and usually only those static methods are used. Thus, it is not a good idea to rely on anything put in the constructor, and I'd really like to avoid burdening all the methods with some kind of enforcement.

Inspired by @EmployedRussian, I achieved:

extern int dummy;

namespace
{
    struct G
    {
        inline G()
        {
            dummy = 0;
        }
    };

    static const G g;
}

But sadly, that performs the assignment once for every unit including the header file.