qt4-mac dependencies - 2 RDBMS?

[Adam Mercer]

Hi

I'm wanting to write a port for some QT based software and looking at
the dependencies for qt4-mac I see that it depends on both mysql5 and
postgresql83, in addition to sqlite:

$ port deps qt4-mac
qt4-mac has build dependencies on:
        pkgconfig
qt4-mac has library dependencies on:
        zlib
        tiff
        libpng
        libmng
        jpeg
        dbus
        unixODBC
        mysql5
        postgresql83
        openssl
        sqlite3
$

Does this really need to depend on two different RDBMS, isn't SQLite
enough? Could variants be added that switch off MySQL and PostgreSQL
support?

Cheers

Adam