Is it possible to "plug" proprietary components into a GNU GPL-licensed application?

Question

C++ / C#

Greetings! In the old days, I wrote an application for a certain competition, which had to be branded under the GNU GPLv2 license, but due to inconsistencies and time, the implementation failed. Now I decided to try my luck again, I almost finished writing it, I included several purchased components there, but as always, only at the end of everything I began to think about the main question. I am writing in Visual C++, DevExpress components (old versions) are built into the application, and it is obvious that the girls are not under the GNU license, so what should I do? It turns out that if I do not exclude them from the application, then it will violate the GNU GPL license and there can be no talk of any participation? Heard about PUEL.

Answer 1

IANAL.
If this is entirely your work, i.e. you did not borrow someone else's code and did not use someone else's libraries protected by the GNU GPL, and did not transfer your copyright to someone (university? employer?), then why not? You are the sole copyright holder, and you can weaken copyleft as much as you like , in particular, you can allow linking with some DevExpress (note that I have no idea what it is, and whether its non- free license allows you to distribute your work, I'm only talking about the GNU GPL ).
Here we have prepared the wording of the copyright notice (the same one that is in all files containing your source code), which gives such permission:

Copyright (C) [года] [имя автора (т. е. ваше)]

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful, 
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, see <http://www.gnu.org/licenses>.

    Additional permission under GNU GPL version 3 section 7

    If you modify this Program, or any covered work, by linking or
    combining it with [название библотеки] (or a modified version of 
    that library), containing parts covered by the terms of [заглавие 
    лицензии этой библитеки], the licensors of this Program grant you
    additional permission to convey the resulting work.

FSF warns : using proprietary libraries is dangerous for your freedom :-)