1) get the GPL code author's permission to use their code under a different licence (LGPL or BSD or whatever), by offering a reasonable share of the profits from the combined work,
2) rewrite the few lines yourself
3) distribute your software on its own and let the user assemble it -- this is what nvidia does with their drivers, or
4) stop distributing the software to other people.
What you can't do is relicence somebody else's code. If your secrecy is so important to you, and the GPL part is only a small fraction of the value, then write those "few lines of code" yourself instead of freeloading.
But this "virus automatic relicencing of all your code GPL" FUD is just FUD.